Camera module for vehicle

ABSTRACT

A camera module for a vision system of a vehicle includes a housing, a circuit element and a lens. The housing has a base portion and a lens portion. The circuit element includes CMOS imaging sensor and associated circuitry. The CMOS imaging sensor has a dynamic range of greater than approximately 100 dB. The dynamic range of the imaging sensor may follow, at least in part, a non-linear response curve. The base portion and the lens portion are welded or sealed together to substantially limit water intrusion into the camera module and the camera module may include shielding to limit or reduce electronic noise. The camera module is configured for mounting at a rear portion of the vehicle so that the imaging sensor has a rearward field of view.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/164,373, filed Jun. 20, 2011, now U.S. Pat. No. 8,982,273,which is a continuation of U.S. patent application Ser. No. 10/534,632,filed May 11, 2005, now U.S. Pat. No. 7,965,336, which is a 371 nationalphase application of PCT Application No. PCT/US2003/036177, filed Nov.14, 2003, which claims priority of U.S. provisional applications, Ser.No. 60/492,544, filed Aug. 5, 2003; Ser. No. 60/477,416, filed Jun. 10,2003; and Ser. No. 60/426,239, filed Nov. 14, 2002, which are all herebyincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to an imaging system for a vehicle and,more particularly, to a camera which may be mounted at an exteriorportion of a vehicle for providing an image of a scene exteriorly of thevehicle. The present invention also relates to an imaging system for avehicle which provides color imaging and a low light imaging capability.

BACKGROUND OF THE INVENTION

The advent of low cost, reliable imaging devices, based on a variety ofsilicon technologies, and in particular CMOS technology, combined withan improved cost/performance ratio for displays capable of meetingautomotive specifications, and an increasing application rate of videomonitor displays for automotive navigation systems or as part of thedriver interface to a wide variety of vehicle systems, has lead to anincreasing use of cameras or imaging sensors designed to give the drivera view of those areas around the vehicle which are not in the normaldirect field of view of the driver, typically referred to as “blindspots”. These areas include the region close to the front of thevehicle, typically obscured by the forward structure of the vehicle, theregion along the passenger side of the vehicle, the region along thedriver's side of the vehicle rearward of the driver, and the area orregion immediately rearward of the vehicle which cannot be seen directlyor indirectly through the rear view mirror system. The camera or imagingsensor may capture an image of the rearward (or sideward or other blindspot area) field of view, and the image may be displayed to the driverof the vehicle to assist the driver in backing up or reversing orotherwise driving or maneuvering the vehicle. The use of electroniccameras in these applications significantly increases the driver'sknowledge of the space immediately surrounding the vehicle, which may beof importance prior to and during low speed maneuvers, and thuscontributes to the safe completion of such maneuvers.

It is thus known to provide a camera or imaging sensor on a vehicle forproviding an image of a scene occurring exteriorly or interiorly of thevehicle to a driver of the vehicle. Such a camera may be positionedwithin a protective housing, which may be closed about the camera orsensor and secured together via fasteners or screws or the like. Forexample, a metallic protective housing may be provided, such as a diecast housing of aluminum or zinc or the like. In particular, for camerasensors mounted on the exterior of a vehicle, protection againstenvironmental effects, such as rain, snow, road splash and/or the like,and physical protection, such as against road debris, dirt, dust, and/orthe like, is important. Thus, for example, in known exterior camerasensor mounts, a butyl seal, such as a hot dispensed butyl seal, or anO-ring or other sealing member or material or the like, has beenprovided between the parts of the housing to assist in sealing thehousing to prevent water or other contaminants from entering the housingand damaging the camera or sensor positioned therein. However, suchhousings typically do not provide a substantially water tight seal, andwater droplets thus may enter the housing. Furthermore, any excessivevibration of the camera sensor, due to its placement (such as at theexterior of the vehicle), may lead to an undesirable instability of theimage displayed to the driver of the vehicle. Also, such cameras orsensors are costly to manufacture and to implement on the vehicles.

Such vehicle vision systems often position a camera or imaging sensor atan exterior portion of a vehicle to capture an image of a sceneoccurring exteriorly of the vehicle. The cameras, particularly thecameras for rearward vision systems, are thus typically placed ormounted in a location that tends to get a high dirt buildup on thecamera and/or lens of the camera, with no easy way of cleaning thecamera and/or lens. In order to reduce the dirt or moisture buildup onthe lenses of such cameras, it has been proposed to use hydrophilic orhydrophobic coatings on the lenses. However, the use of such ahydrophilic or hydrophobic coating on the lens is not typicallyeffective due to the lack of air flow across the lens. It has also beenproposed to use heating devices or elements to reduce moisture on thelenses. However, the use of a heated lens in such applications, whilereducing condensation and misting on the lens, may promote the formingof a film on the lens due to contamination that may be present in themoisture or water. Also, the appearance of such cameras on the rearwardportion of vehicles is often a problem for styling of the vehicle.

Typically, based on consumer preference and at least a perceivedimproved ability to extract information from the image, it is desired topresent a color image to the driver that is representative of theexterior scene as perceived by normal human vision. It is also desirablethat such imaging devices or systems be useful in all conditions, andparticularly in all lighting conditions. However, it is often difficultto provide a color imaging sensor which is capable of providing a clearimage in low light conditions. This is because conventional imagingsystems typically have difficulty resolving scene information frombackground noise in low light conditions.

Silicon-based cameras may be responsive to light in the visible and nearinfrared portions of the spectrum. It is known to filter out theinfrared portion of the energy available to the camera in order tomaintain an appropriate color balance. When this is done, the camerasensitivity may be less than if the near infrared and infrared light wasreceived and used by the camera. Depending on the imaging technologyused, the minimum sensitivities currently economically available forautomotive cameras are typically in the range of 1 to 2 lux and maymaintain a reasonable image quality at light levels at or above suchlevels. However, the conditions on a dark cloudy night where moonlightis obscured, and/or in rural situations in which there is no source ofartificial lighting, may result in a scene illumination as low as about0.01 lux. While the technology continues to improve the low lightsensitivity of silicon based cameras, it is not expected that 0.01 luxcapability will become available in the foreseeable future. Othertechnologies may be capable of such sensitivity, but are notsufficiently cost effective for general application in the automotiveindustry.

Therefore, there is a need in the art for a camera housing thatovercomes the shortcomings of the prior art, and a need in the art foran imaging system that may provide clear, satisfactory images during alldriving or lighting conditions, and thus overcomes the shortcomings ofthe prior art imaging systems.

SUMMARY OF THE INVENTION

The present invention is intended to provide a camera module whichincludes a camera or image sensor and a circuit board positioned withina housing, which may be laser welded or sonic welded or the like tosubstantially seal the camera and circuit board within the housing. Thehousing, preferably molded of a plastic material, may include a plasticmolded connector extending therefrom, such that the camera housing andconnector are configured as a single unitary module. The camera modulemay include a heating element for heating a transparent cover at thelens (or for heating the lens itself) of the camera to assist indefogging or defrosting the transparent cover in cold weatherconditions. The transparent cover may have a transparent conductivecoating (such as an indium tin oxide (ITO) coating or doped tin oxide ora metal grid or the like), preferably on its inner surface, such thatcontact of a power terminal (connected to or in communication with orpowered by a battery or other power source of the vehicle) and a groundterminal of the heating elements at the conductive coating causesheating of the coating to defrost or defog the cover. The heatingelements or terminals may be actuated in response to a control orthermostat, which functions to activate and deactivate the heatingelement at predetermined temperatures sensed by a temperature sensor ator in the camera module or elsewhere at, in or on the vehicle. Thepresent invention thus provides a camera module that maintains thecamera or imaging sensor and is substantially impervious toenvironmental elements, such as rain, snow, dirt, dust, road splash,road debris and the like. The present invention also provides at leastpartial, and preferably substantial, reduced vibration affects of thecamera or image sensor.

According to an aspect of the present invention, a substantially sealedcamera module for an imaging system of a vehicle includes a plastichousing, which preferably includes first and second portions. The firstand second portions are preferably laser welded or sonic welded togetherto substantially seal the camera or sensor and associated componentswithin the plastic housing. The laser welded or sonic welded plastichousing provides a substantially hermetic seal to prevent waterintrusion or the like into the housing. Alternately, and lesspreferably, the first and second portions may be adhesively sealed orjoined.

The camera module may be incorporated into an imaging system thatincludes the sensor and a control for processing images captured by theimaging sensor. The camera module may be positioned within a movablehousing that is movable relative to the vehicle to move the imagingsensor between an in use or operational position, where the imagingsensor is directed toward the exterior scene, and a storage position,where the housing and the imaging sensor are positioned within a portionof the vehicle.

According to another aspect of the present invention, a vented cameramodule for a vehicle includes a plastic housing which is configured toreceive a camera or sensor therein. The housing of the vented cameramodule includes a semi-permeable ventilation area, such as a Gore-Texassembly or area or patch or the like, which is at least partiallypermeable to water vapor and/or is porous enough to allow transfer ofwater vapor into and out from the housing, while substantiallyprecluding entry of water droplets, dirt or the like into the housing.

According to another aspect of the present invention, a camera modulefor a vehicle includes a housing and a transparent cover at a portion ofthe housing. The transparent cover provides a transparent wall of thehousing for the lens and sensor or camera to receive an imagetherethrough. The cover may be heated to defrost or defog the cover incold weather conditions or the like. The cover includes a surface (suchas an inner surface within the housing) which has a conductive coating,such as a coating of indium tin oxide (ITO), doped tin oxide or thelike. The module includes a pair of heater terminals or elements whichcontact the coating, whereby heating of the cover or coating on thecover (such as the inner surface of the cover) is accomplished bygenerating a flow of electricity or electrons or current across thecoating on the cover via the heater terminals or elements.

In one form, one of the heater terminals may be energized or chargedwith electricity and the other terminal may be grounded to the vehicle,such that the electrical current travels from the energized or poweredterminal across the conductive coating to the grounded terminal, therebyheating the conductive coating and, thus, the transparent cover.Preferably, the heater terminals are spaced apart at generally oppositesides or portions of the transparent cover.

Actuation of the heater terminals may defrost or defog the transparentcover and/or may heat the module housing and interior compartment of thecamera module to dry out any moisture within the housing or compartment.In applications where the module includes a ventilation area, such as avented semi-permeable membrane, such as a Gore-Tex assembly or the like,heating of the compartment may be especially suited for driving moistureout of the compartment or module through the ventilation area to limitor substantially preclude moisture condensing within the module.Optionally, the heater terminals may be actuated or energized inresponse to a control, which is operable to energize the heaterterminals or elements in response to a thermostat and/or temperaturesensor positioned at or within the camera module or elsewhere at, in oron the vehicle. Optionally, desiccant material, such as silica gel orthe like, may be included in the housing to absorb moisture which may bepresent within the housing.

According to yet another aspect of the present invention, a cameramodule for a vehicle comprises a housing, a transparent cover at aportion of the housing, an image sensor, at least one heating elementand a control. The image sensor is positioned within the housing and isoperable to receive an image of a scene exteriorly of the housingthrough the transparent cover. The heating element is operable to heatthe transparent cover. The control is operable to activate the heatingelement in response to a temperature sensor. The heating element isactivatable to heat the transparent cover to reduce fog and/or ice onthe transparent cover.

The present invention also provides a camera housing that is movablypositioned at an exterior portion of a vehicle such that the camera maybe moved from a stored position to an in-use or exterior or operationalposition. The camera housing may include a transparent window or paneland may further include a window wiper that functions to wipe dirtand/or moisture or the like from the window or panel as the housingmoves the camera between the stored position and the operationalposition.

According to an aspect of the present invention, a holding device formovably holding an imaging device of a vehicle includes a housing, atransparent panel and a panel cleaning device. The imaging device isoperable to capture an image of a scene occurring exteriorly of thevehicle. The housing is movably mountable at an exterior portion of thevehicle and is configured to receive an imaging device therein. Thehousing is movable relative to the exterior portion of the vehicle tomove the imaging device between a stored position, where the imagingdevice is positioned generally within the portion of the vehicle, and anoperational position, where the imaging device is positioned to have afield of view exteriorly of the vehicle. The transparent panel ispositioned at least partially across an opening of the housing andgenerally in the field of view of the imaging device. The panel cleaningdevice is positionable at the exterior portion of the vehicle andconfigured to engage the transparent panel to clean the transparentpanel as the housing moves the imaging device between the storedposition and the operational position.

According to another aspect of the present invention, an imaging systemfor a vehicle includes an imaging device operable to capture an image ofa scene occurring exteriorly of a vehicle, a control operable to processthe image captured by the imaging device, and a camera housing device.The housing device includes a housing portion defining a compartment, atransparent panel substantially closing an opening of the compartment,and a panel cleaning device. The housing device is movably mountable onan exterior portion of the vehicle. The imaging device is positionedwithin the compartment and directed toward the transparent panel. Thehousing device is movable between a stored position, where the imagingdevice and the transparent panel are positioned at least substantiallywithin the exterior portion of the vehicle, and an operational position,where the imaging device is directed exteriorly of the vehicle and has afield of view directed through the transparent panel and toward theexterior scene. The panel cleaning device is positionable at theexterior portion of the vehicle and configured to engage the transparentpanel to clean the transparent panel as the housing device moves betweenthe stored position and the operational position.

The imaging system may include a display operable to display the imagecaptured by the imaging device. The housing device may be pivotablymountable at the exterior portion of the vehicle, or the housing devicemay be slidably or otherwise movably mountable at the exterior portionof the vehicle. An outer panel of the housing device may define anexterior cover portion at the exterior portion of the vehicle when thehousing device is moved or pivoted to the stored position.

Optionally, the imaging system may comprise a color imaging sensoroperable to capture color images of the exterior scene and an infraredimaging sensor operable to capture infrared images of the exteriorscene. The control may selectively activate one of the color imagingsensor and the infrared imaging sensor in response to the ambient lightintensity present in the exterior scene.

Optionally, the imaging system may include an illumination sourcepositioned within the compartment and directed toward the exterior scenewhen the housing device is moved to the operational position. Thetransparent panel and the compartment are positioned generally withinthe exterior portion of the vehicle when the housing device is moved tothe stored position. Optionally, the control may be operable toselectively activate the illumination source and the imaging device whenthe housing device is moved to the stored position to determine ifmoisture is present on the transparent panel. The housing device mayinclude a heater element that is selectively operable to heat thetransparent panel to reduce moisture present on the transparent panel.

Optionally, the housing device may be movable to selectively positionthe imaging device in first and second operational positions. Thecontrol may be operable to determine a distance to at least one objectin the exterior scene in response to processing of images captured bythe imaging device when the imaging device is in the first and secondoperational positions. For example, the control may be operable toselectively move the housing device to position the imaging device atthe first operational position in response to the vehicle making aninitial approach to a target zone and to position the imaging device atthe second operational position in response to the vehicle movingfurther into the target zone. The imaging device may be directed moredownward when in the second operational position relative to the firstoperational position.

According to another aspect of the present invention, an imaging systemof a vehicle includes an imaging device, a holding device and a control.The imaging device is operable to capture images of a scene occurringexteriorly of the vehicle. The holding device is pivotally mountable ata portion of a vehicle and includes a housing having an exterior paneland a transparent panel. The imaging device is positioned within thehousing. The transparent panel is positioned at least partially acrossan opening of the housing and generally in the field of view of theimaging device. The holding device is pivotable relative to the portionof the vehicle to move the imaging device between a stored position,where the imaging device is positioned generally within the portion ofthe vehicle, and an operational position, where the imaging device ispositioned to have a field of view exteriorly of the vehicle. Theexterior panel is generally aligned with an exterior surface of theportion of the vehicle and the transparent panel is generally within theportion of the vehicle when the imaging device is in the storedposition. The control is operable to process images captured by theimaging device.

The present invention also provides a vehicular imaging system or imagecapture system which is operable to capture an image of an exteriorscene and to display the images at a display of the vehicle. The imagingsystem is operable to control illumination sources operable toilluminate the exterior scene and/or to control the color processing ofthe captured images and/or to control the color/monochromatic status ormode of the image capture device or camera of the system, in order toprovide or display an optimum color or black and white image at thedisplay which has optimum color representation of the scene or hasoptimum illumination or visibility or clarity or contrast ratio in theimage displayed.

For example, the imaging system may selectively activate visible orinfrared or near infrared illumination sources or light emitting diodes(LEDs) in response to a detected ambient light level dropping ordecreasing or lowering to a threshold level. The imaging system may alsoor otherwise selectively switch the imaging sensor from a color mode toa black and white mode in response to the reduced ambient light level.Optionally, the imaging system may apply an infrared contributioncorrection to the detected levels for each color (such as red, green,blue) detected by the imaging sensor to adjust the color balance of theimaging sensor for better color rendition in the captured images.Optionally, the imaging system may provide visible illumination to theexterior scene and may limit or block infrared and near infrared lightpresent in the illuminated scene to reduce processing requirements toobtain the appropriate color balance in the captured images.

Therefore, the present invention provides a camera module for a vehiclewhich may be substantially hermetically sealed to limit or substantiallypreclude water intrusion or the like into the housing of the module, orwhich may be vented to allow for water vapor to enter or exit themodule. The camera housing may also include a heating element which isoperable to defrost or defog the transparent cover of the module and/orto heat the compartment of the camera housing to limit or substantiallypreclude condensation from forming within the module. The heatingelement may be activated and deactivated at predetermined temperaturesin response to a temperature sensor and/or thermostat. The transparentcover of the housing may include a conductive coating on a surfacethereof, such that applying an electrical current or flow through oracross the coating on the surface of the transparent cover functions toheat the surface of the cover to defrost or defog the transparent cover.The present invention thus provides an environmentally resilient,protected, economical camera module which may be mounted to a vehicleand connected or plugged into a wiring connector of the vehicle.

The present invention thus also provides a camera housing device that ismovable or adjustable to move a camera or imaging sensor between anoperational position and a stored position. The camera thus may bepositioned in a stored position within an exterior portion of thevehicle when not in use. The exterior panel of the camera housing devicemay provide an exterior cover at the exterior portion of the vehicle toprotect the camera and lens from the elements when they are not in use.The housing device may include a transparent panel that substantiallyencloses the camera and lens within the housing. The housing device mayalso include a panel cleaning device that may clean the transparentpanel to limit or substantially preclude dirt buildup or debris on thepanel that may adversely effect the performance of the camera and thusof the imaging system.

The present invention also provides an imaging system that is capable ofproviding a color image during daytime conditions, and that may providea black and white image, with or without additional infrared or nearinfrared illumination provided to the scene, during darkened ornighttime conditions. The imaging system may correct the color image toaccount for infrared and near infrared illumination that may be presentin the exterior scene, in order to provide an image with proper ordesired color balance. The present invention thus may provide optimalimages to the driver of the vehicle during substantially all types oflighting conditions.

These and other objects, purposes, advantages and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear perspective view of a vehicle having an imaging systemthereon in accordance with the present invention;

FIG. 2 is a plan view of the vehicle of FIG. 1;

FIG. 3 is a perspective view of a camera module in accordance with thepresent invention;

FIG. 4 is a side elevation of the camera module of FIG. 3;

FIG. 5 is another side elevation of the camera module of FIGS. 3 and 4;

FIG. 6 is an end elevation of the camera module of FIGS. 3-5;

FIG. 7 is a sectional view of the camera module taken along the lineVII-VII in FIG. 6;

FIG. 8 is an opposite end elevation of FIG. 6 of the camera module ofFIGS. 3-7;

FIG. 9 is a sectional view of the camera module taken along the lineIX-IX in FIG. 5;

FIG. 10 is a sectional view of the camera module taken along the lineX-X in FIG. 8;

FIG. 11 is another sectional view of the camera module taken along theline XI-XI in FIG. 8;

FIG. 12A is a side elevation of a camera housing portion of the cameramodule of the present invention;

FIG. 12B is an end elevation of the camera housing portion of FIG. 12A;

FIG. 12C is an opposite end elevation of FIG. 12B of the camera housingportion of FIGS. 12A and 12B;

FIG. 12D is a sectional view of the camera housing portion taken alongthe line D-D in FIG. 12C;

FIG. 13A is a top plan view of a circuit board useful with the cameramodule of the present invention;

FIG. 13B is a side elevation of the circuit board of FIG. 13A;

FIG. 14A is another plan view of the circuit board of FIGS. 13A and 13B,with the circuit board folded over itself;

FIG. 14B is a side elevation of the circuit board of FIG. 14A;

FIG. 15A is a side elevation of a connector portion of the camera moduleof the present invention;

FIG. 15B is an end elevation of the connector portion of FIG. 15A;

FIG. 15C is a sectional view of the connector portion taken along theline C-C in FIG. 15B;

FIG. 15D is another sectional view of the connector portion taken alongthe line D-D in FIG. 15B;

FIG. 15E is an opposite end elevation of FIG. 15B of the connectorportion of FIGS. 15A-D;

FIGS. 16A-D are various views of one side or portion of a metallicprotective shield for the camera module of the present invention;

FIG. 16E is a sectional view of the protective shield taken along theline E-E in FIG. 16D;

FIGS. 17A and 17B are side elevations of an alternate embodiment ofanother camera module and/or components thereof in accordance with thepresent invention, with the connector portion being angled;

FIG. 17C is a perspective view of the connector portion of the cameramodule of FIGS. 17A and 17B;

FIG. 17D is a sectional view of the camera module taken along the lineD-D in FIG. 17B;

FIG. 17E is a sectional view of the camera module taken along the lineE-E in FIG. 17A;

FIG. 18 is a rear perspective view of a vehicle with a camera housingdevice in accordance with the present invention positioned thereon andpositioned in its in-use or operational position;

FIG. 19 is a side elevation and sectional view of a camera housingdevice in accordance with the present invention, with the camera housingdevice positioned so the camera is in its stored position;

FIG. 20 is a side elevation and sectional view similar to FIG. 19, withthe camera housing device positioned so the camera is in its operationalposition;

FIG. 21 is a side elevation and sectional view of another camera housingdevice in accordance with the present invention, with an illuminationsource positioned within the camera housing device and movable with thehousing device and camera;

FIG. 22 is a side elevation and sectional view of another camera housingdevice in accordance with the present invention, with the camera housingdevice being slidable to move the camera between its stored position andoperational position, and with the camera housing device shown in thestored position;

FIG. 23 is a side elevation and sectional view of the camera housingdevice of FIG. 22, with the camera housing device shown in the extendedor operational position;

FIG. 24 is a schematic of an image capture device in accordance with thepresent invention;

FIG. 25 is a block diagram of an imaging system in accordance with thepresent invention; and

FIG. 26 is a perspective view of an imaging system module in accordancewith the present invention, having auxiliary illumination sources.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depictedtherein, an image capture system or imaging or vision system 7 ispositioned at a vehicle 8, such as at a rearward exterior portion 8 a ofthe vehicle 8, and is operable to capture an image of a scene occurringinteriorly or exteriorly of the vehicle, such as rearwardly of thevehicle, and to display the image at a display or display system 9 a ofthe vehicle which is viewable by a driver or occupant of the vehicle(FIGS. 1 and 2). Imaging system 7 includes a camera module 10, which ismountable on, at or in the vehicle to receive an image of a sceneoccurring exteriorly or interiorly of the vehicle, and a control 9 bthat is operable to process images captured by an image sensor 18 ofcamera module 10. Camera module 10 includes a plastic camera housing 11and a metallic protective shield or casing 16 (FIGS. 3-12). Camerahousing 11 includes a camera housing portion 12 and a connector portion14, which mate or join together and are preferably laser welded or sonicwelded together to substantially seal the housing 11 to substantiallylimit or prevent water intrusion or other contaminants from entering thehousing, as discussed below.

Housing 11 of camera module 10 substantially encases a camera or imagesensor or sensing device 18 (FIGS. 7, 9-11, 13A, 13B, 14A and 14B),which is operable to capture an image of the scene occurring exteriorlyor interiorly of the vehicle, depending on the particular application ofcamera module 10. Housing 11 also includes a cover portion 20 at an endof camera housing portion 12. Cover portion 20 provides a transparentcover plate 22 which allows the image of the scene exteriorly orinteriorly of the vehicle to pass therethrough and into housing 11 tocamera 18, and which may be heated to defrost or defog the cover, asdiscussed below. Camera module 10 may include the protective shield 16,which substantially encases camera housing portion 12 and a portion ofconnector portion 14, thereby substantially limiting or reducingelectronic noise going into or out of the camera module and/orprotecting the plastic housing 11 from damage due to impact or the likewith various items or debris that may be encountered at the exterior ofthe vehicle.

Camera module 10 provides a camera or image capture device 18 forcapturing an image of a scene occurring exteriorly or interiorly of avehicle. The captured image may be communicated to a display or displaysystem 9 a which is operable to display the image to a driver of thevehicle. The camera or imaging sensor 18 useful with the presentinvention may comprise an imaging array sensor, such as a CMOS sensor ora CCD sensor or the like, such as disclosed in commonly assigned U.S.Pat. Nos. 5,550,677; 5,670,935; 5,796,094; and 6,097,023, and U.S.patent application Ser. No. 09/441,341, filed Nov. 16, 1999, now U.S.Pat. No. 7,339,149, which are hereby incorporated herein by reference.Camera module 10 and imaging sensor 18 may be implemented and operatedin connection with various vehicular vision systems, and/or may beoperable utilizing the principles of such other vehicular systems, suchas a vehicle headlamp control system, such as the type disclosed in U.S.Pat. Nos. 5,796,094; 6,097,023; 6,320,176; and 6,559,435, and U.S.patent application Ser. No. 09/441,341, filed Nov. 16, 1999, now U.S.Pat. No. 7,339,149; and Ser. No. 10/427,146, filed Apr. 30, 2003, nowU.S. Pat. No. 6,831,261, which are all hereby incorporated herein byreference, a rain sensor, such as the types disclosed in commonlyassigned U.S. Pat. Nos. 6,353,392; 6,313,454; and/or 6,320,176, whichare hereby incorporated herein by reference, a vehicle vision system,such as a forwardly, sidewardly or rearwardly directed vehicle visionsystem utilizing principles disclosed in U.S. Pat. Nos. 5,550,677;5,670,935; 5,760,962; 5,877,897; 5,949,331; 6,222,447; 6,302,545;6,396,397; 6,498,620; 6,523,964; 6,611,202; and 6,201,642, and/or inU.S. patent application Ser. No. 09/199,907, filed Nov. 25, 1998, nowU.S. Pat. No. 6,717,610; Ser. No. 10/372,873, filed Feb. 24, 2003, nowU.S. Pat. No. 6,802,617; Ser. No. 10/011,517, filed Nov. 5, 2001, nowU.S. Pat. No. 6,806,452; Ser. No. 10/324,679, filed Dec. 20, 2002, nowU.S. Pat. No. 6,891,563; Ser. No. 10/047,901, filed Jan. 14, 2002, nowU.S. Pat. No. 6,822,563; Ser. No. 10/643,602, filed Aug. 19, 2003, nowU.S. Pat. No. 7,859,565; and Ser. No. 10/010,862, filed Dec. 6, 2001,now U.S. Pat. No. 6,757,109, which are all hereby incorporated herein byreference, a trailer hitching aid or tow check system, such as the typedisclosed in U.S. patent application Ser. No. 10/418,486, filed Apr. 18,2003, now U.S. Pat. No. 7,005,974, which is hereby incorporated hereinby reference, a reverse or sideward imaging system, such as for a lanechange assistance system or lane departure warning system, such as thetype disclosed in U.S. patent application Ser. No. 10/427,051, filedApr. 30, 2003, now U.S. Pat. No. 7,038,577, which is hereby incorporatedherein by reference, a traffic sign recognition system, a system fordetermining a distance to a leading or trailing vehicle or object, suchas a system utilizing the principles disclosed in U.S. Pat. No.6,396,397, which is hereby incorporated herein by reference, and/or thelike.

Typically, cameras are best suited for uniform lighting conditions, andtypically have a dynamic range of approximately 60 to 70 dB. Thelighting extremes which are encountered in automotive applicationscreate challenges for these cameras. For example, a single framecaptured by the camera may include sunlight reflecting off concretepavement and a dark shadow cast by the vehicle or other object. In sucha situation, standard dynamic range cameras are limited in their abilityto display usable images in both portions of the frame. Either the lightarea may be washed out, or the shadowed area may be black or darkened.

Optionally, and preferably, camera 18 may comprise an extended dynamicrange camera, which may have a dynamic range of greater thanapproximately 100 dB, and preferably approximately 100 to 120 dB. Thelinear dynamic range of the camera or sensor may be extended to above100 dB by programming a non-linear response curve that generally matchesthe response of the human eye. By providing such an extended dynamicrange camera, the camera module may provide an image which is readableand not washed out or darkened in both the highly lighted areas and thedark areas of each frame of the image captured by the camera. Such acamera thus may provide an image to the display or display system whichis readable in both the light and dark regions of each frame.

In a preferred embodiment, the extended dynamic range camera may providea dynamic range of approximately 62 dB in a linear mode andapproximately 110 dB in a non-linear mode. The camera or sensor may havea sensitivity of approximately 5 V/lux.s (if the sensor comprises amonochrome sensor) or approximately 2.7 V/lux.s (if the sensor comprisesa color sensor), and may be operable at a frame rate of approximately 30frames per second. For example, the camera or sensor may comprise aLM9618 Monochrome CMOS Image Sensor or a LM9628 Color CMOS Image Sensor,both of which are commercially available from National Semiconductor.Other suitable cameras or sensors may otherwise be implemented with thecamera module, without affecting the scope of the present invention.

Although shown at a rear portion of a vehicle, camera 18 and cameramodule 10 may be positioned at any suitable location on the vehicle,such as within a rear panel or portion of the vehicle, a side panel orportion of the vehicle, a license plate mounting area of the vehicle, anexterior mirror assembly of the vehicle, an interior rearview mirrorassembly of the vehicle or any other location where the camera may bepositioned and oriented to provide the desired view of the sceneoccurring exteriorly or interiorly of the vehicle. The camera module ofthe present invention is particularly suited for use as an exteriorcamera module. However, the camera module may be positioned at aninterior portion of the vehicle, such as at or in an interior rearviewmirror assembly or accessory module at or near an interior rearviewmirror assembly, to provide an image of an interior scene or of anexterior scene through a window or windshield of the vehicle, withoutaffecting the scope of the present invention. The image captured by thecamera may be displayed at a display screen or the like positionedwithin the cabin of the vehicle, such as at an interior rearview mirrorassembly (such as disclosed in U.S. patent application Ser. No.09/793,002, filed Feb. 26, 2001, now U.S. Pat. No. 6,690,268, which ishereby incorporated herein by reference), or elsewhere at or within thevehicle cabin, such as by using the principles disclosed in U.S. Pat.Nos. 5,550,677; 5,670,935; 5,796,094; 6,097,023 and 6,201,642, and/or inU.S. patent application Ser. No. 09/199,907, filed Nov. 25, 1998, nowU.S. Pat. No. 6,717,610, which are hereby incorporated herein byreference.

As best shown in FIGS. 7 and 9-12, camera housing portion 12 includes agenerally cylindrical portion 12 a extending outwardly from a baseportion 12 b. Camera portion 12 comprises a molded plastic component andmay include a pair of heater terminals or elements 30 a, 30 b insertmolded within and/or along the walls of cylindrical portion 12 a, asdiscussed below. Cylindrical portion 12 a receives a lens or opticsystem 24 therein, which functions to focus the image onto camera orsensor 18, which is positioned at a circuit board 26 mounted within thebase portion 12 b of camera housing portion 12.

Lens system 24 is positioned within cylindrical portion 12 a of cameraportion 12 so as to receive light from the exterior or interior scenethrough cover 22 at end 12 c of camera portion 12. Lens system 24 ismounted to, such as via threaded engagement with, camera cover orhousing 28, which functions to substantially cover or encase camera orsensor 18 to substantially prevent or limit incident light from beingreceived by camera 18 and interfering with the image received by camera18 through cover 22 and lens system 24. The lens system 24 may be anysmall lens or lens system which may focus an image of the sceneexteriorly of the camera module onto the camera or image sensor 18, suchas, for example, the types disclosed in U.S. Pat. No. 6,201,642; and/orin U.S. patent application Ser. No. 10/010,862, filed Dec. 6, 2001, nowU.S. Pat. No. 6,757,109, which are hereby incorporated herein byreference. The lens system 24 may provide a wide-angle field of view,such as approximately 120 degrees or more.

Cover portion 20 is mounted at an outer end 12 c of camera housingportion 12 opposite from base portion 12 b, as shown in FIGS. 7 and9-11. Cover portion 20 includes an outer circumferential ring or coverretainer 20 a, which engages an outer surface of transparent cover 22and functions to retain transparent cover 22 in position at the end 12 cof the cylindrical portion 12 a of camera receiving portion 12.Preferably, circumferential ring 20 a is laser welded or sonic welded orotherwise joined or bonded to outer end 12 c of cylindrical portion 12 aof camera receiving portion 12, as discussed below. The laser or sonicwelding of the seam substantially seals and secures cover portion 20onto camera receiving portion 12, and may limit or substantiallypreclude any water intrusion or contaminant intrusion into the camerareceiving portion at the outer end 12 c. Preferably, an inner surface 22a of transparent cover 22 includes a transparent conductive coating forheating the cover, as also discussed below.

In the illustrated embodiment, base portion 12 b is generally square anddefines a generally square mating edge 12 e around the base portion 12 bfor mating and securing to a corresponding edge 14 g of connectorportion 14, as discussed below. Base portion 12 b receives circuit board26 and camera 18 therein, while a camera housing or shield 28 and lensor lens system 24 extend into cylindrical portion 12 a of camera portion12 to receive the image through transparent cover 22.

Connector portion 14 of housing 11 is a molded plastic component andincludes a connector terminal or connector 14 a, such as a multi-pinsnap-on connector or the like, extending from a base portion 14 b. Baseportion 14 b is formed (such as in a square shape as shown in theillustrated embodiment) to substantially and uniformly mate or connectto base portion 12 b of camera housing 12, as can be seen with referenceto FIGS. 7 and 9-11. The base portions 12 b and 14 b mate together anddefine a pocket or space for receiving and securing circuit board 26therein. Base portions 14 b and 12 b may be laser welded or sonic weldedtogether at their mating joint or connection 13. Laser or sonic weldingof the joint melts the plastic edges or seams together to substantiallyhermetically seal housing 11 to prevent water intrusion or othercontaminant intrusion into housing 11 of camera module 10. Optionally,and less desirably, the base portions may be otherwise joined orsubstantially sealed together (such as via suitable adhesives and/orsealants). The module may optionally include a vented portion orsemi-permeable membrane to vent the module, as discussed below. The baseportions 12 b and 14 b may further include mounting tabs or flanges 12d, 14 f, which extend outwardly from base portion 12 b, 14 b. Mountingtabs 12 d, 14 f are generally aligned with one another when the baseportions are secured together and include an aperture therethrough formounting the camera module 10 at or to the vehicle via suitablefasteners or the like (not shown). Although shown as having generallysquare-shaped mating portions, connector portion 14 and camera portion12 may have other shaped mating portions or surfaces, without affectingthe scope of the present invention.

Multi-pin connector 14 a extends from base portion 14 b and includes aplurality of pins or terminals 14 c for electrically connecting cameramodule 10 with a connector (not shown) of the vehicle. For example, oneend 14 d of terminals 14 c may connect to circuit board 26, while theother end 14 e of terminals 14 c connects to the corresponding connectorof the vehicle. The corresponding connector may partially receive theends 14 e of pins or terminals 14 c at multi-pin connector 14 a and maysnap together with multi-pin connector 14 a via a snap connection or thelike. As best shown in FIGS. 15A, 15C and 15D, ends 14 d of terminals 14c protrude or extend from connector portion 14, such that the ends 14 dmay be received within corresponding openings or apertures 26 c incircuit board 26 when housing portion 11 is assembled, as discussedbelow.

As shown in FIGS. 3-11, connector portion 14 may provide a generallystraight multi-pin connector extending longitudinally from the baseportion of the housing 11. However, other shapes of connectors, such asangled connectors or bent connectors or the like, such as a 90 degreeangle connector portion 14′ of a camera module 10′ (FIGS. 17A-E),discussed below, may be implemented, depending on the particularapplication of the camera module, without affecting the scope of thepresent invention.

Optionally, camera module 10 may comprise a substantially hermeticallysealed module, such that water intrusion into the module is limited orsubstantially precluded. Base portion 12 b of camera housing portion 12and base portion 14 b of connector portion 14 are correspondingly formedso as to substantially mate or join together at their mating seam 13,whereby the portions may be laser welded or sonic welded together orotherwise joined, while cover portion 20 is also laser welded or sonicwelded or otherwise secured and substantially sealed at the opposite end12 c of camera portion 12, in order to substantially seal the camerahousing. Laser or sonic welding techniques are preferred so as to jointhe materials at a state where they are able to re-flow, either viaheat, vibration or other means, such that the materials re-flow andcross-link and become a unitary part. Such joining results in asubstantially hermetically sealed camera module. Additionally, the poresin the plastic as well as any voids around the insert molded pins andstampings may be sealed with a Loctite material or other suitablesealing material, to further limit or substantially preclude entry ofwater droplets and/or water vapor into the housing of the substantiallysealed module.

Optionally, or alternately, the camera module of the present inventionmay comprise a vented module, which allows for water vapor to enterand/or exit the housing, while substantially precluding water dropletsand the like from entering the housing. The camera portion 12 orconnector portion 14 may include a semi-permeable ventilation portion ormembrane 15 (FIG. 10), which preferably comprises a material or membranewhich is at least partially permeable to water vapor and/or is porousenough to allow for ventilation of water vapor, but does not allow waterdroplets to pass therethrough, such that water vapor may enter and exitthe housing 11, while water droplets and the like are kept outside thehousing 11. For example, the ventilation portion 15 may comprise aGore-Tex material or the like. In such applications where the modulecomprises a vented module and includes a ventilation portion, it is notnecessary that the seams of the housing be laser welded or sonic welded,since the substantially hermetic sealing of the seams of the modulewould not be critical when the module is vented. Optionally, desiccantmaterial, such as silica gel or the like, may be included in the housingto absorb moisture which may be present within the housing.

Camera housing portion 12 also includes a pair of heating terminals 30a, 30 b which extend from within base portion 12 b to outer end 12 csubstantially along/or within the walls of cylindrical portion 12 a.Preferably, the terminals 30 a, 30 b are insert molded within thecylindrical wall of camera portion 12 a. As shown in FIGS. 7 and 12D,the ends 30 c of terminal portions 30 a, 30 b extend downward into baseportion 12 b of camera receiving portion 12, for connection to circuitboard 26, as discussed below. The opposite ends 30 d of terminals 30 a,30 b extend radially inward at outer end 12 c of cylindrical portion 12a and may provide arcuate or semicircular contacts at inner surface 22 aof transparent cover 22 (FIGS. 7, 12B and 12C). A power or positiveterminal 30 a may be insert molded along and at least partially withinthe cylindrical portion 12 a and positioned generally along an interiorportion of the cylindrical portion 12 a, while a ground or negativeterminal 30 b is insert molded along and partially within cylindricalportion 12 a and positioned along an exterior wall or surface of thecylindrical portion 12 a (as can be seen in FIGS. 7 and 12D). Theexteriorly positioned ground terminal 30 b may contact the metallicprotective shield 16, discussed below, to ground the shield to theheating device and/or camera module.

Heating device 30 functions to heat inner surface 22 a of transparentcover 22, in order to defrost or defog the cover 22. Heating device 30may also function to heat the inside or interior compartment of housing11, in order to maintain the temperature within the housing above athreshold temperature to further limit or substantially precludemoisture from condensing within the camera housing. This is especiallyuseful when implemented in a vented module having a semi-permeablemembrane or portion, whereby the heater may generate heat to dry out anddrive out any moisture within the camera body compartment. The heatedcamera module thus may substantially preclude moisture from condensingwithin the module, since the water vapor would otherwise condense on thecoldest surface available within the module.

The power heater terminal 30 a may be connected to or in communicationwith the vehicle battery or other power source and may be energizable toprovide electrical current to inner surface 22 a of transparent cover22, while the ground terminal 30 b provides a ground connection for theheating device. Energization of terminal 30 a thus causes electricalcurrent or electrons to flow across the inner surface 22 a of cover 22to ground terminal 30 b. Preferably, inner surface 22 a of transparentcover 22 includes a transparent conductive coating or layer, such as anindium tin oxide (ITO) coating or a doped tin oxide coating or the like,such as the types of layers or coatings used in electro-optic orelectrochromic mirror technology and as disclosed in U.S. Pat. Nos.5,140,455; 5,151,816; 6,178,034; 6,154,306; 6,002,544; 5,567,360;5,525,264; 5,610,756; 5,406,414; 5,253,109; 5,076,673; 5,073,012;5,117,346; 5,724,187; 5,668,663; 5,910,854; 5,142,407 and 4,712,879,which are hereby incorporated herein by reference. Preferably, theconductive coating or layer provides a resistance of less thanapproximately 80 ohms per square, and more preferably less thanapproximately 20 ohms per square. The conductive coating generates heatas electrons or electricity flow from contact 30 d of power terminal 30a across surface 22 a to contact 30 d of ground terminal 30 b. Thecontacts 30 d are spaced apart at generally opposite sides of thetransparent cover 22 and provide for generally uniform and thoroughheating of inner surface 22 a when electricity is applied to heatingterminal 30 a. As can be seen in FIGS. 12B and 12C, contacts 30 d ofterminals 30 a, 30 b are preferably semicircular or half moon shapedcontacts to extend substantially across each side of the cover 22,without interfering with the central region of the cover through whichthe scene may be viewed by the camera and lens.

Preferably, circuit board 26 of camera module 10 also includes a heatercircuit for controlling the heater device 30 and heater terminals 30 a,30 b in response to a temperature sensor (not shown). The heater circuitmay be operable to actuate the heater device 30, such as via energizingheater terminal 30 a, when the temperature at, within or near the cameramodule (or elsewhere at, in or on the vehicle) drops to a thresholdtemperature. The control or circuit is also operable to deactivate theheating device at a second predetermined threshold temperature. Theheating device thus is operable via a thermostatic circuit which mayactivate and deactivate the heating device to heat the transparent cover22 and/or the interior compartment of the housing when the temperatureis detected to be low enough to warrant such activation. Such athermostatic circuit may be operable to activate the heater elementswhen it is most desirable to heat the transparent cover and/or theinterior of the housing and, thus, may limit or substantially precludefogging or freezing of cover 22 and/or moisture condensing within thehousing, while limiting or substantially precluding operation of theheating device in circumstances or situations when heat is not requiredon the transparent cover or in the housing.

As best shown in FIGS. 13A, 13B, 14A and 14B, circuit board 26 includesa camera mounting circuit board 26 a, which is connected to a connectorreceiving circuit board 26 b via a multi-wire ribbon wire 27 or thelike. Camera mounting circuit board 26 a is mounted or secured to thebase portion 12 b of camera portion 12, while connector circuit board 26b is mounted or secured to the base portion 14 b of connector portion14. Camera or image sensor 18 is mounted at a surface of camera circuitboard 26 a, and is substantially encased at circuit board 26 a by cameracover 28 and lens 24 (FIGS. 7 and 9-11). As shown in FIGS. 7, 13A and14A, camera circuit board 26 a includes a pair of apertures 26 c forreceiving ends 30 c of heating terminals 30 a, 30 b. Likewise, connectorcircuit board 26 b includes a plurality of openings or apertures 26 dfor receiving ends 14 d of connector terminals 14 c therethrough (FIGS.7, 10, 11 and 13A). The ends of the pins or terminals may be soldered inplace in their respective openings. As shown in FIGS. 9, 11 and 14B,circuit board 26 is folded at ribbon wire 27, such that circuit board 26a generally overlaps circuit board 26 b when they are positioned withinthe base portions 12 b, 14 b of the camera housing. The circuit board 26may thus fold to an open position after the separate boards 26 a, 26 bare secured within their respective base portions of the housing tofacilitate soldering of the connector terminals or heater terminals atthe respective circuit boards. After all of the connections are made,the housing may be folded to its closed position and laser welded orsonic welded together or otherwise joined or bonded together tosubstantially seal the circuit board within the housing.

Optionally, the exterior surface 22 b of cover 22 (which may be exposedto the atmosphere exterior of the camera module) may be coated with ananti-wetting property such as via a hydrophilic coating (or stack ofcoatings), such as is disclosed in U.S. Pat. Nos. 6,193,378; 5,854,708;6,071,606; and 6,013,372, the entire disclosures of which are herebyincorporated by reference herein. Also, or otherwise, the exterior oroutermost surface 22 b of cover 22 may optionally be coated with ananti-wetting property such as via a hydrophobic coating (or stack ofcoatings), such as is disclosed in U.S. Pat. No. 5,724,187, the entiredisclosure of which is hereby incorporated by reference herein. Suchhydrophobic property on the outermost surface of the cover can beachieved by a variety of means, such as by use of organic and inorganiccoatings utilizing a silicone moeity (for example, a urethaneincorporating silicone moeities) or by utilizing diamond-like carboncoatings. For example, long-term stable water-repellent andoil-repellent ultra-hydrophobic coatings, such as described in PCTApplication Nos. WO0192179 and WO0162682, the entire disclosures ofwhich are hereby incorporated by reference herein, can be disposed onthe exterior surface of the cover. Such ultra-hydrophobic layerscomprise a nano structured surface covered with a hydrophobic agentwhich is supplied by an underlying replenishment layer (such as isdescribed in Classen et al., “Towards a True ‘Non-Clean’ Property:Highly Durable Ultra-Hydrophobic Coating for Optical Applications”, ECC2002 “Smart Coatings” Proceedings, 2002, 181-190, the entire disclosureof which is hereby incorporated by reference herein).

In the illustrated embodiment, camera module 10 includes a protectiveshield or casing 16 which partially encases the plastic housing 11 andfunctions to limit or reduce electronic noise which may enter or exitcamera module 10 and may protect the plastic housing from damage fromimpact of various items or debris which the camera module may encounterat the exterior portion of the vehicle. The protective shield or casing16 includes a pair of casing portions 16 a (one of which is shown inFIGS. 16A-16E). Each of the casing portions 16 a partially encases abouthalf of the plastic housing 11 of camera module 10 and partiallyoverlaps the other of the casing portion 16 a, to substantially encasethe plastic housing within protective shield 16. Each of the portions 16a includes a slot 16 b for receiving the mounting tabs 12 d, 14 ftherethrough for mounting the camera module at the desired location atthe vehicle. Each casing portion 16 a includes overlapping portions 16 cwhich overlap an edge of the other casing portion 16 a to assemble thecasing 16 around the plastic housing. The casing portions 16 a may bewelded, crimped, adhered, banded, or otherwise joined or securedtogether about the plastic housing 11, in order to encase the housing11. Preferably, protective shield 16 comprises a metallic shield andcontacts ground terminal 30 b of heating device 30 at the exteriorsurface of the cylindrical portion 12 a of camera receiving portion 12and, thus, may be grounded to the heating device and/or the cameramodule or unit via the ground terminal 30 b, as can be seen withreference to FIG. 7. Protective shield 16 may comprise a stamped metalshielding or may be formed by vacuum metalizing a shield layer over theplastic housing 11, or may comprise a foil or the like, withoutaffecting the scope of the present invention.

With reference to FIGS. 17A-17E, a camera module 10′ is shown whichincludes a connector portion 14′ of a housing 11′ which provides for a90 degree bend in the connector pins or terminals 14 c′ to accommodatedifferent mounts or connections to a connector of the vehicle. Otherbends or shapes of the molded connector portion may be implementedwithout affecting the scope of the present invention. The othercomponents of camera module 10′ are substantially similar to therespective components of camera module 10, discussed above, such that adetailed discussion of those components will not be repeated herein. Thecommon components are shown in FIGS. 17A-17E with the same referencenumbers as assigned to the respective components of camera module 10 ofFIGS. 1-16.

Therefore, the present invention provides a sealed camera module whichmay provide a substantially watertight and substantially hermeticallysealed housing about a camera or image sensor of the camera module. Thehousing components may be laser welded or sonic welded together whichsubstantially seals the plastic housing and substantially precludeswater intrusion or the like into the housing at the seams or matingportions of the housing. Because the plastic housing of the cameramodule of the present invention may be laser welded or sonic weldedtogether to substantially seal the housing, the housing may provide aneconomical and rugged, environmentally resilient and protective housingfor the camera or sensor and circuit board. The unitary housing andconnector also makes it easy to install and connect the camera module toa vehicle connector.

Alternately, the camera module of the present invention may comprise avented camera module, where the housing includes a semi-permeableventilation or venting portion, such as a Gore-Tex assembly, area orpatch or the like, which allows for ventilation of water vapor into andout from the housing, while substantially precluding entry of waterdroplets or dirt or other contaminants or the like into the housing. Theplastic vented module of the present invention thus may also provide aneconomical and rugged, environmentally resilient and protective housingfor the camera or sensor and circuit board.

Additionally, the camera module of the present invention may include aheating device which functions to heat a transparent conductive coatingon a transparent cover of the housing, so as to provide heat to thecover to defrost or defog the cover. The heater elements may be insertmolded within the plastic housing of the camera module and may plug intoa circuit board received within the housing as the camera module isassembled. Preferably, the heating device may be operable in response toa temperature sensor, such that the heating device may be activated whenthe temperature drops to a threshold temperature and then deactivatedafter the temperature has been elevated to a second higher thresholdtemperature. The heating device is thus automatically operable in lowtemperature levels when it may be desirable to activate the heatingdevice. The heating device may be activated to defrost or defog thetransparent cover of the camera module and/or to heat the interiorchamber of the camera module to limit or substantially preclude moisturecondensing therein. Heating the interior compartment of the cameramodule may dry out any moisture within the module and may limit orsubstantially preclude condensation from forming within the module. Inapplications where the camera module comprises a vented camera module,the heat generated within the vented camera module may also drive outwater vapor through the semi-permeable ventilation area to further limitor substantially preclude water vapor from condensing within the cameramodule.

Referring now to FIGS. 18-20, a camera housing device 110 may house orcontain a camera or imaging device 116 and protect the camera fromexposure to the elements in applications where the camera may bepositioned at a vehicle 8 (FIG. 18) for viewing an area or sceneexterior of the vehicle. The camera housing device 110 may be positionedat least partially within an opening 8 b at an exterior portion 8 a of avehicle 8 (such as a rearward portion or side portion or elsewhere onthe vehicle). The housing device 110 defines a compartment or cavity 114for receiving camera or imaging device 116 therein and is operable ormovable to move the camera or imaging device 116 between a storedposition (FIG. 19) and an operational or extended or in-use position(FIG. 20). The camera 116 and compartment 114 are positioned generallyinwardly of an outer panel or flap 118 of housing device 110 at theexterior portion 8 a of the vehicle 8 when the housing device and cameraare in the stored position. As shown in FIG. 19, the outer panel or flap118 is positioned generally along the exterior portion 8 a of thevehicle a and serves as a cover or flap over the opening 8 b whenhousing device 110 is in its stored position.

Imaging device 116 may be operable in conjunction with a vision orimaging system of the vehicle, such as a reverse or backup aid system,such as a rearwardly directed vehicle vision system utilizing principlesdisclosed in U.S. Pat. Nos. 5,550,677; 5,760,962; 5,670,935; 5,760,962;5,877,897; 5,949,331; 6,222,447; 6,302,545; 6,396,397; 6,498,620;6,523,964; 6,611,202; and/or 6,201,642, and/or in U.S. patentapplication Ser. No. 09/199,907, filed Nov. 25, 1998, now U.S. Pat. No.6,717,610; Ser. No. 10/372,873, filed Feb. 24, 2003, now U.S. Pat. No.6,802,617; Ser. No. 10/011,517, filed Nov. 5, 2001, now U.S. Pat. No.6,806,452; Ser. No. 10/324,679, filed Dec. 20, 2002, now U.S. Pat. No.6,891,563; Ser. No. 10/047,901, filed Jan. 14, 2002, now U.S. Pat. No.6,822,563; and Ser. No. 10/643,602, filed Aug. 19, 2003, now U.S. Pat.No. 7,859,565; and Ser. No. 10/010,862, filed Dec. 6, 2001, now U.S.Pat. No. 6,757,109, which are hereby incorporated herein by reference, atrailer hitching aid or tow check system, such as the type disclosed inU.S. patent application Ser. No. 10/418,486, filed Apr. 18, 2003, nowU.S. Pat. No. 7,005,974, which is hereby incorporated herein byreference, or an imaging system that may utilize aspects of otherimaging or vision systems, such as the types disclosed in U.S. patentapplication Ser. No. 10/054,633, filed Jan. 22, 2002, now U.S. Pat. No.7,195,381; and Ser. No. 09/793,002, filed Feb. 26, 2001, now U.S. Pat.No. 6,690,268, which are hereby incorporated herein by reference. Theimaging system includes a control or control system or device that isoperable to process images captured by the imaging device 116 and adisplay 115 (FIG. 1) for displaying the captured images to a driver oroccupant of the vehicle. The display may be positioned at an interiorportion of the vehicle, such as at an interior rearview mirror assemblyof the vehicle or accessory module of the vehicle or the like. Thedisplay may comprise a video display screen at a mirror assembly, suchas the type disclosed in U.S. provisional applications, Ser. No.60/439,626, filed Jan. 13, 2003; Ser. No. 60/489,812, filed Jul. 24,2003; and Ser. No. 60/492,225, filed Aug. 1, 2003, which are herebyincorporated herein by reference, or may comprise other types ofdisplays or display systems, such as, for example, a display on demandtype of display, such as the types disclosed in commonly assigned U.S.Pat. Nos. 5,668,663 and 5,724,187, and U.S. patent application Ser. No.10/054,633, filed Jan. 22, 2002, now U.S. Pat. No. 7,195,381; and Ser.No. 09/793,002, filed Feb. 26, 2001, now U.S. Pat. No. 6,690,268, whichare hereby incorporated by reference herein, without affecting the scopeof the present invention.

The control may also be operable to move the camera housing devicebetween the operational and stored positions. The method of actuation ofthe housing to move the housing and camera may be accomplished by amotor, such as via a gear or screw mechanism, or by vacuum compressedair or by magnetic or electromagnetic means, such as in the form of asolenoid or the like. Optionally, the camera housing device 110 may bemovable to the operational position in response to an engagement of thereverse gear of the vehicle, or in response to an actuation of a backupaid or other reverse viewing system of the vehicle. Optionally, thecamera housing may be moved to the operational position in response to auser input or the like, without affecting the scope of the presentinvention. The camera housing thus allows for occasional use of thecamera and may store and protect the camera when the camera is not inuse.

Imaging device or camera 116 may comprise a camera device or other imagecapturing device, such as a video camera or sensor, such as a CMOSimaging array sensor, a CCD sensor or the like, such as the typesdisclosed in commonly assigned, U.S. Pat. Nos. 5,550,677; 5,760,962;6,097,023 and 5,796,094, which are hereby incorporated herein byreference. Such imaging array sensors comprise an array of photo-sensingpixels to sense light present in the field of view of the sensor. Theimaging device 116 may comprise a color sensing imaging device, whichincludes color filters such that the photo-sensing pixels of the imagingdevice sense particular colors of light from the scene. Optionally, theimaging device may or may not include an infrared filter to filter orattenuate infrared or near infrared light present in the exterior scene.Optionally, the imaging device may provide an infrared sensingcapability to provide enhanced performance of the imaging device duringnighttime and/or darkened conditions where the visible light intensityis reduced. Optionally, the housing device may include two separateimaging devices, one for sensing color light for daytime lightingconditions and one for sensing infrared light for nighttime or darkenedlighting conditions, as discussed below. Alternately, the control may beoperable to selectively switch the imaging sensor between a color modeand a monochromatic mode, such as via utilization of principlesdescribed below with respect to imaging system 310. The imaging devicemay have a lens 117 positioned in front of the sensor, and may utilizeaspects of an imaging module of the types described above with respectto the camera modules 10, 10′ of FIGS. 1-17.

Housing device 110 mounts or attaches the camera 116 generally at theexternal flap 118, such that the movement of the external flap betweenits opened position (FIG. 20) and its closed position (FIG. 19) movesthe camera between its operational position and its stored position. Thereverse aid camera or imaging device 116 is thus mounted behind the flap118 such that when the camera is not in use it may be retracted into thevehicle exterior portion or body portion 8 a, thereby protecting it fromthe elements, such as dirt or debris or the like, and keeping the lens117 relatively clean. The outer flap 118 may partially overlap the edgesof the opening 8 b in exterior portion 8 a of vehicle 8 and may begenerally aligned with an outer or exterior surface of the exteriorportion to provide a generally flush, finished appearance to theexterior portion 8 a when the housing device 110 is in the stored orclosed position.

As shown in FIGS. 19 and 20, the camera 116 may be mounted in a housingor box or container 119 attached to the flap 118, such that the camera116 is substantially contained or encased within the compartment 114defined within the housing 119. The housing device 110 may definecompartment or cavity 114 within and between an inner wall or flap 120and external flap 118, and opposite side walls or flaps 122 (only oneside wall shown in FIGS. 19 and 20). The housing 119 of camera housingdevice 110 may be pivotable about a generally horizontal pivot axis orpin 111 at the exterior portion 8 a of the vehicle 8. In the illustratedembodiment, housing device 110 includes a pivot arm or extension 111 aextending from inner wall 120. The pivot arm 111 a pivotally mounts to apivot pin 111 and may pivotally move or swing the housing 119 betweenthe stored position and the operational position. The pivot pin or axis111 may be positioned within the exterior portion 8 a of the vehicle 8and generally adjacent to the edge of the opening 8 b in the exteriorportion 8 a.

Optionally, the housing device may be positioned at a side portion ofthe vehicle (such that the housing may pivot about a generally verticalpivot axis or the like) or at a generally horizontal portion of thevehicle (such that the housing may pivot about a generally horizontalpivot axis and may have an outer flap that is generally horizontal whenin its closed orientation, with the camera and housing positionedgenerally above or below the closed flap, depending on the particularapplication) or elsewhere on or in the vehicle, without affecting thescope of the present invention.

Housing 119 may include a clear or transparent glass or plastic windowor panel 124 that at least partially closes the compartment 114 and thatis positioned generally in front of the camera or imaging device 116 andcovers or generally encases the lens 117 of the camera or imaging device116. The transparent panel 124 may comprise a visible light transmittingpanel that may substantially transmit visible light present in the sceneto the imaging sensor 116 within housing 119 and behind transparentpanel 124. The transparent panel 124 may comprise a substantially clearor transparent panel to provide protection to the lens and imagingsensor within the housing. Optionally, the transparent panel maycomprise or provide an optical lens or may have optical qualities orcharacteristics or properties, whereby the transparent panel mayfunction to serve or augment the lens of the imaging sensor.

Optionally, a wiper blade or wiping or cleaning device 126 may bepositioned at the opening 8 b of the exterior portion 8 a of the vehicle8 and may engage or wipe the outer surface 124 a of the transparentpanel 124 as the housing device 110 moves between the stored positionand the operational position, in order to brush or clean or wipe debrisor dirt or the like from the transparent panel 124. The wiper blade ordevice 126 may be spring loaded or biased (such as via a flexible springclip 126 a or the like) into engagement or contact with the surface 124a of the window or panel 124 such that as the housing device 110 opensand closes, the wiper 126 engages and wipes and cleans the window 124.

The transparent panel 124 thus may comprise a curved or arcuate panelsuch that the wiping device 126 generally uniformly engages the outersurface of the transparent panel as the housing device is opened andclosed. However, the transparent panel may comprise other forms (and maybe a generally flat panel), whereby the wiping device may engage only adesired portion of the panel or may be biased more toward the panel tomaintain engagement of the wiping device with the panel during movementof the housing device. Optionally, a washer jet 128 may also bepositioned at or near the opening 8 b and may be operable to spraywasher fluid or the like toward the panel or window 124 to clear dirtfrom the panel or window and to limit or prevent scratching of thewindow by the wiper.

Optionally, the housing device 110 may include a heating element that isoperable to heat the transparent panel or window 124 to reduce moisturethat may be present on the window. For example, window 124 may be heatedby conductive strips embedded in the window, or surface mountedconductive strips, or ITO coatings or similar conductive orsemi-conductive coatings or the like, such as described above withrespect to camera module 10, 10′. The heater thus may heat the window tolimit or substantially avoid condensation obscuring the field of view ofthe camera. Optionally, condensation may be limited by the use of adesiccant substance or by venting the enclosure or the like, withoutaffecting the scope of the present invention.

Optionally, the exterior surface 124 a of window 124 may be coated withan anti-wetting property such as via a hydrophilic coating (or stack ofcoatings), such as is disclosed in U.S. Pat. Nos. 6,193,378; 5,854,708;6,071,606; and 6,013,372, the entire disclosures of which are herebyincorporated by reference herein. Also, or otherwise, the exteriorsurface 124 a of window 124 may optionally be coated with ananti-wetting property such as via a hydrophobic coating (or stack ofcoatings), such as is disclosed in U.S. Pat. No. 5,724,187, the entiredisclosure of which is hereby incorporated by reference herein. Suchhydrophobic property on the outermost surface of the window or panel canbe achieved by a variety of means, such as by use of organic andinorganic coatings utilizing a silicone moeity (for example, a urethaneincorporating silicone moeities) or by utilizing diamond-like carboncoatings. For example, long-term stable water-repellent andoil-repellent ultra-hydrophobic coatings, such as described in PCTApplication Nos. WO0192179 and WO0162682, the entire disclosures ofwhich are hereby incorporated by reference herein, can be disposed onthe exterior surface of the window. Such ultra-hydrophobic layerscomprise a nano structured surface covered with a hydrophobic agentwhich is supplied by an underlying replenishment layer (such as isdescribed in Classen et al., “Towards a True ‘Non-Clean’ Property:Highly Durable Ultra-Hydrophobic Coating for Optical Applications”, ECC2002 “Smart Coatings” Proceedings, 2002, 181-190, the entire disclosureof which is hereby incorporated by reference herein).

In some applications, it may be advantageous and desirable to addadditional illumination to the exterior scene being captured by thecamera. Accordingly, a camera housing device 110′ may house or containan imaging device or camera 116 and an illumination source or auxiliarylight 130 (FIG. 21) that is operable to direct illumination toward thefield of view of the camera 116. The illumination source 130 may providevisible light, infrared or near infrared light or may be pulsed toprovide pulsed infrared or near infrared light. The auxiliary light 130may be fixedly positioned on the external bezel portion of the camerahousing or of the exterior portion of the vehicle, or optionally, andpreferably, may be positioned within the housing and as part of thecamera housing device or assembly (such as shown in FIG. 21). In thisway, the panel 125 in front of the illumination device 130 may also becleaned by the same operation or wiper 126 that cleans the transparentpanel 124′ in front of the camera 116.

Under some conditions, the light from the auxiliary illumination source130 may be reflected, piped or refracted in or along the compartmentand/or transparent panel in such a way that it may interfere with theimage captured by the camera. Such interference may be avoided bysplitting the clear window (as shown in FIG. 21) such that there is awindow or panel 124′ in front of the camera and a second window or panelor section 125 in front of the illumination source 130. Optionally, adivider or separating wall or panel or baffle 132 may be positionedbetween the compartments 114 a, 114 b that contain the camera 116 andillumination source 130, respectively. In the illustrated embodiment,the camera transparent panel 124′ is substantially flat or planar, whilethe light transparent panel 125 is curved or arcuate. However, thetransparent panels 124′, 125 may be other shapes, without affecting thescope of the present invention. The separate panels and baffle provide anon-continuous path for the light to travel, so that the light will nothave an adverse affect on the images being captured, while stillproviding for the external surface or surfaces of the panel or panels tobe cleaned by the same wiper device. Optionally, by splitting the windowinto two panels 124′, 125, the panel 125 covering the auxiliary lightmay be colored, such as red, to improve the appearance of the product onthe vehicle. The camera housing device 110′ is otherwise substantiallysimilar to camera housing device 110, discussed above, such that adetailed discussion of the camera housing device will not be repeatedherein.

Optionally, to improve the performance of the camera, the light level orintensity of the light emitted by the auxiliary light may be monitoredby a sensor or device or control, and a control circuit may be used toadjust the camera for different light levels. Such a camera adjustmentsystem would enhance the performance of the camera over a wide range oflight conditions, and may also be used to control the auxiliary light ifdesired.

Optionally, when the camera housing is in the closed position, thecamera and the auxiliary light may be at least occasionally turned on toilluminate the enclosed cavity and to capture an image of theilluminated enclosed cavity and transparent window. The enclosed cavityprovides a known image, and the images captured by the camera in thisorientation may be used to examine the window for condensation, dirt orother abnormalities. If condensation is detected on the window, a heateror heating mechanism may be activated to dry or evaporate the moisturefrom the window. The camera thus may be used to control the heaters thatare used to remove condensation from the window. Optionally, if heatingthe window or cleaning the window does not alleviate a detectedabnormality (such as if the same abnormality is detected after two ormore openings and closings of the housing device), the control mayprovide an indication to a user of the imaging system that thetransparent window may need to be checked or replaced (in case theabnormality detected is a chip or scratch or crack or the like that mayadversely effect the performance of the imaging system).

Because the camera housing device is adjustable and may move the camera,the camera housing device of the present invention may provide theability to change the field of view. For example, the camera can bemoved to the furthest out or fully extended position for an initialapproach to a parking zone or target zone or area. As the vehiclefurther enters the parking zone, the camera can be adjusted or moved toa more vertical angle (by pivoting or moving the housing devicepartially toward the closed position) to display the proximity of thebumper to any obstacle in the exterior scene. Such an adjustment of thecamera position or orientation may also be combined with a change oradjustment of the lens configuration, such as by using a longer focallength for the initial approach (which may provide a less distorted viewor image) and a wider angle configuration for the close range viewing toprovide a wider field of view to the driver of the vehicle during theback up or reverse driving or maneuvering of the vehicle.

Also, by using the folding adjustment of the camera housing device toadjust the position of the camera, the housing device and camera may beadjustable to provide a different view of the area behind the vehicle.The control of the imaging system may then be operable to process imagescaptured in each of the views and may compare the images to determinedistances to objects detected in the exterior scene (such as byutilizing principles disclosed in U.S. Pat. No. 6,396,397; and/or inU.S. patent application Ser. No. 10/427,051, filed Apr. 30, 2003, nowU.S. Pat. No. 7,038,577, which are hereby incorporated herein byreference). By electronic comparison of the images captured between twopositions of the camera (capturing at least one image in each of the twoviews), a distance map can be produced. Such a distance map may then beused to provide additional information about the exterior scene to thedriver of the vehicle.

Optionally, the housing may not be restricted to one camera and mayinstead house or include two cameras for different imaging situations.For example, a standard color camera could be used for daylightconditions, while an infrared camera may be used for night or darkenedconditions. The infrared or night camera may comprise a CMOS camera orthe like without color or infrared filtering, such that it may be highlysensitive to infrared light that is present in the visibly darkenedscene. The control may selectively activate the appropriate camera orimaging sensor in response to the ambient light level or intensitypresent at the exterior scene, such as in response to an ambient lightsensor or in response to a light detection by one or both of the imagingsensors or the like. When the night camera is operated or used, thecontrol may also activate (such as continuously activate or pulse) aninfrared or near infrared illumination source at the exterior portion ofthe vehicle (such as within the compartment of the housing device, asdiscussed above). Optionally, a single camera or imaging sensor may beswitched between a color mode and a monochromatic mode (such asdescribed below with respect to imaging system 310), and an infraredillumination source may be activated when in the monochromatic mode, toenhance the performance of the camera or imaging sensor in variouslighting conditions.

Although shown as being positioned at a rearward portion of a vehicle,the camera housing device of the present invention may be positionedelsewhere on the vehicle, such as a forward portion of the vehicle or asideward portion of the vehicle or a roof portion of the vehicle or thelike, without affecting the scope of the present invention. Also,although the camera housing device is shown as being mounted on a nearlyvertical body portion of the vehicle, the camera housing device may bemounted or positioned at a nearly horizontal surface (such as may befound in the top of a number plate appliqué or the like), withoutaffecting the scope of the present invention. In such a horizontalmounting application, the flap of the housing device may drop down toexpose the clear window and to move the camera into its operationalposition.

Referring now to FIGS. 22 and 23, a camera housing device 210 holds orcontains a camera or imaging device 216 and is movably mounted to anexterior portion 8 a of a vehicle. The housing device 210 is movable tomove the camera 216 (and associated lens 217) between a stored position(FIG. 22) and an operational position (FIG. 23). Housing device 210includes a housing portion 219 that defines the cavity or compartment214 within an outer panel or flap 218, an inner panel 220 and sidepanels 222 (one side panel is shown in FIGS. 22 and 23). A transparentcover 224 may close a portion of the cavity and may be positionedgenerally in front of the imaging device, such that imaging device has afield of view through the transparent window or panel and toward theexterior scene, as discussed above. Housing device 210 is generallylinearly slidable relative to the exterior portion 8 a of the vehicle(such as via a linear motor, an electromagnetic device or solenoid, apneumatic device and/or the like) to extend outward from the exteriorportion of the vehicle when in the operational position, as shown inFIG. 23.

The housing device 210 thus may be generally linearly moved outward andinward relative to the vehicle portion 8 a. Accordingly, the transparentpanel 224 may be a substantially flat or planar panel, such that thewiper device 226 (such as a wiper blade or the like on a spring orbiasing member or the like 226 a) may engage and wipe the surface 224 aof the panel 224 as the panel is moved along adjacent to the wiperdevice 226. Optionally, the housing device 210 may be generally tubularor even generally cylindrical in shape, such that the transparent panelis curved, while the wiper device is correspondingly curved tosubstantially uniformly engage the curved or tubular transparent panelas the housing device is moved between the stored and operationalpositions. The wiping motion of the wiper on the transparent window orpanel may thus be achieved by making the camera housing device agenerally tubular construction that slides in and out in a generallylinear motion, whereby the wiper can then clean the transparent windowas the housing device moves in and out. The housing device 210 mayotherwise be substantially similar to the housing device 110, 110′,discussed above, such that a detailed discussion of the housing devicewill not be repeated herein.

Therefore, the present invention provides a camera housing device thatcontains a camera and lens of an imaging system at or partially withinan exterior portion of a vehicle. The camera housing device is movableor adjustable to move the camera between an operational position and astored position. The camera thus may be positioned in a stored positionwithin an exterior portion of the vehicle when not in use. The exteriorpanel of the camera housing may provide an exterior cover at theexterior portion of the vehicle to protect the camera and lens from theelements when they are not in use. The housing device may include atransparent panel that substantially encloses the camera and lens withinthe housing. The housing device may also include a panel cleaning devicethat may clean the transparent panel to limit or substantially precludedirt buildup or debris on the panel that may adversely effect theperformance of the camera and thus of the imaging system.

Referring now to FIGS. 24-26, an image capture system or imaging orvision system 310 is positioned at an exterior portion of a vehicle,such as at a rearward portion 8 a of the vehicle 8 (FIGS. 1 and 2), andis operable to capture an image of a scene occurring exteriorly of thevehicle, such as rearwardly of the vehicle, and to display the image ata display or display system 314 of the vehicle which is viewable by adriver of the vehicle. Image capture system 310 includes an imagecapture device or camera 316 (such as a camera or camera module of thetypes described above), which is directed exteriorly of the vehicle andhas an exterior field of view which at least partially encompasses a“blind spot” area exteriorly of the vehicle. The images or framescaptured by image capture device 316 are displayed at display 314 toassist the driver in viewing the blind spot areas, such as the rearwardarea immediately behind the vehicle for backing up or otherwise drivingor maneuvering the vehicle. The image capture system 310 may include oneor more auxiliary illumination sources 318 (FIG. 26), which may beselectively operable to provide illumination within the field of view ofthe image capture device 316 to enhance the illumination of the exteriorscene. The image capture system 310 may also include a control orcontrol system or microcontroller or microprocessor 320 for controllingor adjusting the image capture device and/or the illumination sources inresponse to the light levels in the general vicinity of the imagingsystem or in response to the contrast ratio in the captured image. Forexample, the microcontroller may selectively activate one or moreillumination sources or LEDs 318, or may selectively switch the imagingsensor 316 from a color mode to a monochromatic or black and white mode,or may apply an infrared or near infrared contribution correction to thecolor levels of the pixels of the imaging sensor to adjust the colorbalance for better color rendition in the captured images, in responseto the ambient light levels or contrast ratio, as discussed below.

Image capture system 310 may be positioned at the exterior portion ofthe vehicle and directed generally exteriorly of the vehicle forcapturing images of the exterior scene to assist the driver inmaneuvering or driving the vehicle. Image capture system 310 may utilizeprinciples of other vehicle vision or imaging systems, such as aforwardly, sidewardly or rearwardly directed vehicle vision system orimaging system or the like utilizing principles of the systems disclosedin U.S. Pat. Nos. 5,550,677; 5,670,935; 5,760,962; 5,796,094; 5,877,897;5,949,331; 6,097,023; 6,201,642; 6,222,447; 6,302,545; 6,313,454;6,320,176; 6,353,392; 6,396,397; 6,498,620; 6,523,964; 6,559,435; and6,611,202, and U.S. patent application Ser. No. 09/441,341, filed Nov.16, 1999, now U.S. Pat. No. 7,339,149; Ser. No. 10/427,146, filed Apr.30, 2003, now U.S. Pat. No. 6,831,261; Ser. No. 09/199,907, filed Nov.25, 1998, now U.S. Pat. No. 6,717,610; Ser. No. 10/372,873, filed Feb.24, 2003, now U.S. Pat. No. 6,802,617; Ser. No. 10/011,517, filed Nov.5, 2001, now U.S. Pat. No. 6,806,452; Ser. No. 10/324,679, filed Dec.20, 2002, now U.S. Pat. No. 6,891,563; Ser. No. 10/047,901, filed Jan.14, 2002, now U.S. Pat. No. 6,822,563; Ser. No. 10/643,602, filed Aug.19, 2003, now U.S. Pat. No. 7,859,565; and Ser. No. 10/010,862, filedDec. 6, 2001, now U.S. Pat. No. 6,757,109, which are hereby incorporatedherein by reference. The imaging system may be operable to capturesimages of the scene immediately rearward of the vehicle to assist thedriver of the vehicle in backing up or maneuvering the vehicle inreverse. The back up assist system may be operable in response to thereverse gear of the vehicle being selected.

Image capture device or camera or imaging sensor 316 may comprise animaging array sensor or a pixelated imaging array, such as a multi-pixelarray such as a CMOS sensor or a CCD sensor or the like, such as thetypes disclosed in commonly assigned U.S. Pat. Nos. 5,550,677;5,670,935; 5,796,094; 6,097,023; and 6,498,620, and U.S. patentapplication Ser. No. 09/441,341, filed Nov. 16, 1999, now U.S. Pat. No.7,339,149; and Ser. No. 09/793,002, filed Feb. 26, 2001, now U.S. Pat.No. 6,690,268, which are hereby incorporated herein by reference, orsuch as an extended dynamic range camera, such as the types describedabove. For example, the imaging sensor may comprise a CMOS camera, suchas the OV7930 single chip CMOS color NTSC camera available fromOmniVision Technologies Inc. of Sunnyvale, Calif. Such color cameras mayhave the performance characteristics identified above and mayadditionally provide RGB and/or YCrCb video signals. Preferably, thecolor video camera operates at a minimum illumination (3000 K) of lessthan about 5 lux at f1.2, more preferably of less than about 3 lux atf1.2, and most preferably less than about of less than about 2 lux atf1.2. Such CMOS imaging sensors typically may have a peak sensitivity inthe near infrared range, such as at approximately 850 nm to 900 nm.

Such pixelated imaging sensors may include a plurality of pixels, withat least some of the pixels masked or covered with a particular colorfilter, such that the individual pixels function to capture a particularcolor, such as red, green and blue colors or the like, such as disclosedin U.S. Pat. Nos. 5,550,677; 5,670,935; 5,796,094; 6,097,023; and6,498,620, referenced above. For example, the imaging sensor 16 maycomprise an individual blue or a green or a red color filter over eachpixel element of the CMOS multi-pixel element array. The imaging sensoris thus operable to provide color images to the display. Such RGBfilters enable the capture of a color image by the CMOS detector, butnecessarily result in a reduced or decreased low light level sensitivityfor a color camera compared to a monochromatic or black and whitecamera. Optionally, and preferably, the imaging sensor may be capable ofselectively operating in either a color mode, in which a color image maybe displayed on display 314, or a monochromatic or black and white mode,in which a monochromatic or black and white image may be displayed ondisplay 314, such as by utilizing aspects of the imaging sensordisclosed in U.S. Pat. No. 6,498,620, which is hereby incorporatedherein by reference.

In the illustrated embodiment of FIG. 26, the image capture device 316is at least partially contained within an imaging module or cameramodule 322, which includes imaging sensor or camera 316 and a lens 324positioned within a housing (such as similar to housing 11 of cameramodule 10, discussed above) which defines a transparent window 322 a(which may comprise an at least substantially transparent glass orpolycarbonate or acrylic (or other suitable material) window or panel)at the end of lens 324 (such as described above with respect to cameramodule 10, 10′). The imaging module 322 may include the circuitry andcontrols for imaging sensor 316, such as on one or more printed circuitboards 322 b (FIG. 26) contained within the housing. The imaging module322 is shown in FIG. 26 without the housing for purposes of clarity.

As shown in FIG. 26, imaging module 322 may be positioned at or adjacentto a plurality of illumination sources 318 to define an imaging systemmodule 323. The illumination sources 318 may be operable to emit orproject illumination in the general direction that the imaging sensor316 and lens 324 are directed. Preferably, the illumination sourcesproject or emit substantially uniform illumination directly behind thevehicle where the vehicle back up lights do not typically provideadequate illumination. The illumination sources may be selected toprovide sufficient intensity over the targeted area to maintain theminimum acceptable contrast ratio (such as about 18 dB) in the displayedimages.

The illumination sources 318 may comprise infrared or near infraredemitting light emitting diodes (LEDs) or the like and thus may emitlight or energy in the infrared or near infrared range (such as energyhaving a wavelength of approximately 750 nm or greater). The infraredillumination may be provided via pulsing the illumination sources orgenerally continuously activating the illumination sources. An exemplarynear-infrared emitting LED to use in conjunction with the imaging systemof the present invention is available from Lumex Inc. of Palatine, Ill.under the trade name OED-EL-1L2. This is a T-5 mm, leaded, clear epoxy−60 degree LED that emits essentially no visible light but that has apeak spectral emission of about 940 nm. Forward current through suchinfrared LEDs is typically less than about 150 mA, more preferably lessthan about 100 mA, and most preferably less than about 80 mA. Powerconsumption by such infrared LEDs is typically less than about 350 mW,more preferably less than about 250 mW, and most preferably is less thanabout 150 mW. Such LEDs can be powered by duty cycling, such as by pulsewidth modulation or by direct current drive (typically via a loaddropping resistor in series with the vehicle ignition supply). Othernear-infrared light emitting diodes or the like can be used, such asLEDs with a peak light emission intensity at about 730 nm, at about 780nm, at about 875 nm, and at about 880 nm. Spectral output for suchnear-infrared LEDs is preferably in the 5 mW/sr to about 35 mW/sr range.Such near-infrared light emitting diodes emit little or no visiblelight.

The infrared or near infrared illumination thus may provide improvedcamera pixel responsivity in low light levels, and the projectedinfrared or near infrared illumination is not readily visible directlybehind the vehicle when the illumination sources are activated. Thewavelength of the illumination emitted by the illumination sources maybe selected to best balance the camera spectral response and to minimizeambient lighting affects in the captured image. Optionally, auxiliaryillumination sources may be selected that emit visible light, asdiscussed below. Optionally, additional visible light sources (such asvisible light emitting LEDs or an incandescent source or a neon sourceor the like) can illuminate on occasions at night when the driver wantsto have visible light illumination of the area immediately exteriorly ofthe vehicle. Optionally, the auxiliary illumination may be provided viaactivation of modified back up lights, which may provide visible orinfrared or near infrared illumination at the area immediately rearwardof the vehicle, such as when the vehicle is shifted to the reverse gear.

With reference to FIG. 25, imaging system 310 includes microcontroller320, which is operable to control imaging sensor 316 and auxiliaryillumination sources 318. The microcontroller 320 may receive an inputsignal from one or more ambient light sensors 326, which are operable todetect the ambient light levels within the exterior scene. Themicrocontroller may provide an active camera control and may be operableto adjust or control the imaging sensor and/or the illumination sourcesin response to the ambient light levels present in the exterior scene.Optionally, the microcontroller may process the captured image todetermine the contrast ratio in the images. The microcontroller may thenadjust or control the imaging sensor and/or the illumination sources inresponse to the contrast ratio in order to maintain the image displaycontrast ratio at a minimum acceptable viewing contrast ratio. Forexample, the microcontroller may activate or increase the illuminationoutput of the illumination sources to increase the contrast ratio in thecaptured images to a desired or threshold minimum ratio or level, suchas approximately 18 dB.

The imaging sensor 316 may receive or capture images via imaging lens324 and a bandpass filter 328, all of which may be positioned behind thetransparent window of camera module 322. The images captured by imagingsensor 316 may be received by an image processor 330 and data translator332, which may process the images or pixel outputs as desired. Forexample, the image processor 330 and data translator 332 may be operableto process the images to determine if an object is present in thedetected image, such as by utilizing the principles disclosed in U.S.patent application Ser. No. 10/427,051, filed Apr. 30, 2003, now U.S.Pat. No. 7,038,577, which is hereby incorporated herein by reference, ormay process the captured images to extract other information therefrom,without affecting the scope of the present invention. The datatranslator 332 may also receive inputs 333 pertaining to vehicle data orvehicle status data or the like. The images captured may be displayed atthe display or display system 314, and/or the processed images orinformation derived or extracted from the processed images may bedisplayed at the display or display system 314.

During normal day time conditions or high ambient light conditions (forexample, when the ambient light sensor or sensors 326 detect an ambientlight level which is greater than a threshold light level or when themicrocontroller determines that the contrast ratio of the capturedimages is greater than the minimum acceptable viewing contrast ratio),imaging sensor 316 may provide color images which provide a colorrendition consistent with the driver's expectations (in other words,consistent with real world colors). The imaging sensor or camera may beswitched or set to a color mode when ambient light levels are at orincrease to a sufficient level at or above a minimum or threshold level,and thus may capture color images and may provide color images to thedisplay system during such lighting conditions. The camera or system mayalso include an automatic color balance algorithm which may function toadjust or optimize the colors in the captured image to the visiblespectrum of light, as discussed below.

As disclosed in U.S. Pat. Nos. 5,550,677; 5,670,935; 5,796,094;6,097,023; and 6,498,620, and U.S. patent application Ser. No.09/441,341, filed Nov. 16, 1999, now U.S. Pat. No. 7,339,149; and Ser.No. 09/793,002, filed Feb. 26, 2001, now U.S. Pat. No. 6,690,268, whichare hereby incorporated herein by reference, the pixels of the imagingarray sensor 316 may be individually operable to measure a particularcolor or range of color (such as red, green and blue) in the visiblespectrum to determine the color image. Any near infrared radiation orinfrared radiation that is received by the pixels may add to themeasured value of the particular color that the particular pixel sensesor accumulates. This results in a shift in the representation in thecolor of the captured image and may result in an image havingunsatisfactory or unrepresentative color. Optionally, and as discussedbelow, the band pass filter 328 of the imaging system may comprise aninfrared or near infrared filter, which may filter out or substantiallyblock light in the infrared and/or near infrared range of the spectrum,such as light having wavelengths in the approximately 750 to 900 nm, andpreferably blocking or reducing transmission of some light in thevisible region of the electromagnetic spectrum so that band pass filter328 passes (i.e. is highly transmitting to) visible wavelengths up toabout 650 nm or thereabouts, but has reduced transmission above about650 nm and, in particular, has substantially reduced transmission in thenear infrared region.

In order to correct the color balance in the captured images, the imagecapture system of the present invention may subtract fixed values fromthe particular color values (e.g., red, green, blue) of each pixel, suchthat the imaging system may provide an infrared or near infraredcontribution correction in situations where the infrared or nearinfrared light present in the scene (such as from solar radiation) mayotherwise washout or distort or otherwise adversely affect the colorbalance of the captured images. The offset or subtracted values may be agenerally fixed intensity offset or value or may be based on the ambientlight levels detected by the ambient light sensor or by a combination ofpixels of the imaging sensor or the like.

Optionally, the infrared radiation present in the exterior scene may bemeasured, such as via an infrared sensor positioned at the lens 324,imaging sensor 316 or window 322 a of camera module 322. The measuredinfrared radiation may be factored into the infrared contributioncorrection amount to provide an improved and dynamic correction for thepixels. It is further envisioned that the offset for the particularcolors (e.g., red, green, blue) may be different between the colors (forexample, in certain lighting conditions, there may be more of an offsetfor one color, such as, for example, red, than the other color orcolors, such as green and blue). The imaging system may thus provide adetection of the infrared radiation and may provide a dynamic correctionof each pixel color. The imaging system thus may provide a sensor drivenoffset or correction. The sensor or sensors may comprise an infraredsensor (with a visible light filter) by itself or in combination with asecond sensor which senses visible light (with an infrared filter), todetermine the infrared level or intensity in the exterior scene.

Optionally, some of the pixels of the imaging array sensor 316 may beunmasked or unfiltered, such that they capture or accumulate the entirespectrum of light (or at least substantially the entire spectrum oflight) present in the scene. The unmasked pixels thus are dedicated tosensing the visible and infrared light present in the exterior scene andmay provide a basis for determining the offset that is to be applied tothe color value of the masked pixels. In such an embodiment, the imagecapture device would not include an infrared filter, or at least not aninfrared filter over the entire pixelated array (however, an infraredfilter at the pixel level may be provided, such as an infrared filter ateach of the individual color pixels, which also include a mask or filterassociated with the particular color that the individual pixel is tocapture).

The imaging sensor 316, which may comprise a CCD or CMOS camera or thelike, may thus operate sufficiently well with its factory settings atillumination levels between a few lux and several thousand lux (such asmay be present in normal indoor lighting conditions). When the availableambient illumination is below these levels, however, the camera may havea difficult time distinguishing features in the captured image ascompared to the background noise of the camera, and thus may not be ableto maintain the minimum contrast ratio during such low light levels. Toaddress this deficiency, the auxiliary illumination sources 318 may beselectively activated to project auxiliary illumination throughout thefield of view of the camera, in order to provide sufficient illuminationlevels for the camera to operate properly. The illumination sources maybe selectively activated or controlled by the microcontroller inresponse to the ambient light levels detected by ambient light sensor orsensors 326 or by imaging sensor 316 (such as in response to a detectionthat the ambient light level has dropped or reduced to a thresholdreduced light level), or in response to the contrast ratio in thecaptured image (such as in response to the contrast ratio being lessthan a desired or threshold amount, such as approximately 18 dB).

Optionally, the auxiliary illumination sources 318 may emit or projector provide visible light to the exterior scene. In such applicationswhere visible light is provided by the auxiliary illumination sources(or where sufficient visible light may be provided by the backup lightsor other lights or illumination sources of the vehicle), the band passfilter 328 may comprise an infrared or near infrared filter (or visiblelight pass filter) and may provide a cutoff or block at approximately650 nm, such that the near infrared and infrared spectral regions (andpreferably a portion of the visible light region of the spectrum) arelimited or blocked from the imaging sensor or camera 316. Becausegreater visible illumination may thus be provided via the illuminationsources in low ambient light conditions, while the infrared and nearinfrared illumination present in the exterior scene may be filtered orsubstantially blocked, the imaging system may be capable of capturingimages during such lighting conditions which may have acceptable colorbalance, or which may require a reduced amount of processing or coloradjustment to achieve the appropriate or acceptable color balance andcontrast ratio. The filter pass or cutoff wavelength range may beselected to tailor the filter cutoff wavelength to the particularapplication (depending on the illumination provided to the exteriorscene and the capabilities of the imaging sensor). The imaging systemthus may provide improved imaging capabilities in low light conditions,while providing an appropriate color balance and contrast ratio for theimages captured in all ambient lighting conditions.

In applications where the auxiliary illumination source or sourcescomprise infrared or near infrared illumination sources or LEDs, themicrocontroller may switch the color camera from the color mode (wherethe camera captures color images and the display displays color images)to a monochromatic or black and white mode (where the camera capturesmonochromatic images). The microcontroller may switch the imaging sensorto the black and white mode in response to the ambient light leveldropping to the threshold level or in response to the illuminationsources being activated. Such a monochromatic mode is preferred inreduced visible lighting conditions and/or when the infrared emittingillumination sources are activated because the automatic color balancealgorithm of the imaging system functions to optimize the color in thecaptured image to the visible spectrum, and may not function as well insuch infrared or non-visible lighting conditions. Once the infrared ornear infrared illumination is introduced by the illumination sources,the color balance control may be insufficient, which may result in awashed out or distorted image. The black and white image provided by theblack and white mode may thus be more pleasing for viewing by the driverof the vehicle during such lighting conditions. The image sensor mayquickly switch between the color mode and black and white mode and mayprovide a smooth transition from one mode to the other.

With reference to FIG. 25, the following illustrates the sequence ofevents that may trigger or initiate the low-light mode of the imagingsystem of the present invention. The microcontroller 320 may read orreceive an output from one or more ambient light sensors 326, which maybe positioned at or near imaging sensor 316 and which may be operable todetect or sense the ambient light present in the exterior scene. Themicrocontroller may also determine the contrast ratio of the imagesbeing captured by the imaging sensor. When the ambient light levels aredetermined to be below a low-light mode calibrated value or thresholdvalue (or when the contrast ratio drops below the threshold level), themicrocontroller may then initiate new commands to the imaging sensor orcamera 316, such as via an I2C serial link or the like. The new registercommands may consist of defeating the automatic gain, exposure and colormodes of the imaging sensor 316. The exposure may be set to maximumframe integration time and the amplifier gain may, for example, be setto ½ maximum. This combination provides an enhanced or optimal signal tonoise ratio for such lighting conditions.

The microcontroller may enter the monochromatic or color defeat mode,whereby the microcontroller may select either a single color killregister or a combination of modifying the color matrix registers tonegate the color balance of the imaging sensor. The microcontroller mayalso enable the infrared LEDs via a logic control signal or the like, sothat infrared or near infrared illumination is provided to the exteriorscene. The low light mode camera settings may then be maintained untilone or more of the ambient light sensors returns values or signals tothe microcontroller which are above or outside the calibrated orthreshold low-light mode range. Once this occurs, the imaging sensor maybe set to the color mode and the above mentioned registers may be againupdated with new values, and the illumination sources or LEDs may bedisabled. The imaging sensor, such as a CMOS camera or the like, mayimplement the register updates within approximately two frame times(i.e., the time it takes to capture two consecutive frames or images),which may be within approximately 66 ms, depending on the particularimaging sensor used with the imaging system of the present invention.

Because the imaging system of the present invention may correct forwashout or distortion in the color values to account for infrared andnear infrared illumination in the exterior scene, and because theimaging system may switch to a monochromatic mode when conditions darkenand/or when the illumination sources are activated, the presentinvention may obviate the need or desirability of providing an infraredfilter at the imaging sensor, since such a filter may filter out some ofthe infrared or near infrared illumination provided by the illuminationsources when the imaging system is in the low light mode. However, it isenvisioned that such a band pass filter or infrared filter element mayoptionally be provided at the imaging sensor to attenuate at least someof the infrared radiation that may be present in the exterior scene. Forexample, an infrared filter may be provided that is highly transmitting(such as an integrated photopic visible transmission of at least about75% transmitting, more preferably at least about 80% transmitting, andmost preferably at least about 85% transmitting) in the visible lightregion between about 300 nm and 800 nm (where the eye's photopicresponse is sensitive), and more preferably in the 400 nm to 700 nmspectral range, and that has a lower or reduced transmissivity or islowly transmitting in the 800 nm to 1100 nm region (at least) with aspectral transmission in the 750 nm to 1100 nm of less than about 5%transmission preferred, less than about 3% more preferred, and less thanabout 1% most preferred. Such infrared filter elements typically consistof a transparent substrate (typically glass) coated with a multilayerstack (typically at least three layers, more preferably at least fivelayers, most preferably at least seven layers, and typically depositedby vacuum deposition such as by sputtering or evaporation) of metaloxides and similar dielectric thin film layers that form a broad bandvisible band pass filter with a sharp spectral cut off around 700 nm orso. Such infrared filters typically operate by light interference, andpreferably act as cold mirrors reflecting away near-infrared radiationwhile being highly transmitting to visible light. An example of aninfrared filter element suitable for use with the imaging system of thepresent invention is available from Maier Photonics, Inc. of ManchesterCenter, Vt. under the part designation “p/n SP730/14s”. This filterelement has a 50% cut-off at +/−10 nm at normal incidence, and comprisesa 1 mm thick soda-lime glass substrate. Alternately, a WBHM infraredfilter element available from OCLI of Santa Rosa, Calif. can be used(which has an average transmission equal to or greater than 80% fromapproximately 400 nm to 700 nm and an average transmission less than orequal to 2% from approximately 750 nm to 1100 nm). Also, an infraredfilter element from Evaporated Coatings, Inc. of Willow Grove, Pa.comprising a Corning Micro-Sheet Glass 0211 coated with ECI#1010 can beused. This filter element has an average transmission equal to orgreater than 85% at 400 nm to 700 nm; a partial transmission of about80% at 740 nm (+/−10 nm); a partial transmission of about 50% at 750 nm(+/−10 nm); and an average transmission of less than about 3% at 780 nmto 1100 nm. Such infrared filter elements are abrasion resistant perMIL-C-675A, which is hereby incorporated by reference herein. Suchinfrared filters may be disposed in the camera assembly in front of theCMOS or CCD imaging array sensor (either in front of the camera lens orbetween the camera lens and the video detector array).

However, a problem can arise when a camera equipped with an infraredelement as described above is used in conjunction with near infraredlight emitting sources such as those also described above. The nearinfrared cut off of the camera filter may also severely attenuate and/orblock the near infrared radiation emitted by the near infrared LEDs (orsimilar near-infrared emitting sources) such that nighttime illuminationmay be inadequate to be useful/valued by the driver. In order to avoidsuch concerns, while still providing such an infrared filter, theinfrared filter and illumination sources may be selected such that atleast some of the infrared illumination emitted by the illuminationsources is not filtered or blocked by the infrared filter. For example,the filter may be selected that may cut out or substantially blockradiation having wavelengths above approximately 950 nm, while theillumination source may emit light having wavelengths of approximately800 nm to 900 nm. Optionally, and as discussed above, the auxiliaryillumination sources may be operable to emit or project visible light toprovide adequate visible illumination to the exterior scene, whereby theinfrared and near infrared light may not be required by the imagingsensor (and thus may be filtered or blocked, such as at a wavelength ofapproximately 650 nm and above) in order to provide appropriate clarityand color balance in the images captured by the imaging sensor.

Optionally, it is further envisioned that the imaging system mayfunction to remove the infrared filter from in front of the imagingsensor when the infrared illumination sources are activated, such asdescribed in U.S. patent application Ser. No. 09/793,002, filed Feb. 26,2001, now U.S. Pat. No. 6,690,268, which is hereby incorporated hereinby reference. For example, at nighttime when ambient lighting is low andthe infrared emitting illumination sources are activated, the infraredfilter element may be moved out of the field of view of the lens so thatthe detector or camera can view unattenuated infrared radiation from theinfrared emitting illumination sources so that the output image in thevideo display is discernable by the driver. Various means can be used toremove the infrared filter element from the camera field of view duringnighttime. For example, an electromechanical mechanism, preferablyoperated by the microcontroller in response to a photo sensor or ambientlight sensor, can automatically move the infrared filter element, suchas by electrical command, out of the line of sight or field of view ofthe imaging sensor when the ambient lighting conditions are low.

Optionally, electro-optic means can be used to prevent color wash out byday while maximizing low light sensitivity by night. For example, anelectrochromic infrared filter can be used, such as a filter utilizingthe principles disclosed in U.S. Pat. No. 6,426,492, and U.S. patentapplication Ser. No. 10/206,558, filed Jul. 26, 2002, now U.S. Pat. No.6,667,471, which are hereby incorporated herein by reference. The filtermay include a tungsten oxide electrochromic layer that changes frombeing substantially visible light transmitting and substantiallynear-infrared transmitting when uncharged (bleached) and transforms tobeing significantly near-infrared absorbing/reflecting as well as beingsignificantly visible light attenuating when cathodically charged. Thedegree of near-infrared attenuation and visible light attenuation isproportional to the negative voltage applied to the electrochromictungsten oxide metal oxide layer, with applied voltages in the 0.1 V toabout 2.5V range typical. The higher the cathodic voltage applied, themore the near-infrared/visible light attenuation.

Optionally, the imaging system of the present invention may additionallyinclude a plurality of infrared shutters which are in the optical paththe imaging array sensor, such as disclosed in U.S. Pat. No. 6,498,620,which is hereby incorporated herein by reference. Each infrared shutterhas at least one state in which infrared energy is generally notattenuated to the imaging sensor. In another state, the infrared shuttergenerally blocks infrared radiation from the array. The state of theinfrared shutters may be controlled by the microcontroller, which maycontrol the shutters in response to the ambient light levels in theexterior scene, such as detected by the ambient light sensor or sensors.During periods of high image luminance, the infrared shutters may switchto a state in which the shutters block near infrared radiation from theimaging sensor. However, during low image luminance conditions, theinfrared shutters may switch to a state in which the shutters allow thenear infrared energy to be transmitted to the imaging sensor. Theaddition of the near infrared radiation at low luminance levels enhancesthe image luminance sensed by the imaging sensor. The imaging sensor mayalso be switched to the monochromatic or black and white mode duringsuch low luminance levels. The infrared shutters may be eitherelectrochromic shutters or liquid crystal shutters, both of which areknown in the art.

Although many aspects of the present invention are particularly suitablefor applications having a CMOS type image sensor or camera (due to thehigh infrared sensitivity of CMOS cameras), other types of cameras orsensors may be implemented, such as CCDs, etc., without affecting thescope of the present invention.

Therefore, the present invention provides an imaging system which mayprovide enhanced imaging during nighttime conditions, while providingoptimal color imaging during daytime conditions. The imaging system maydetermine the ambient light levels at the exterior scene, such as viaambient light sensors or photosensors, which may be associated with thecamera or imaging array sensor, or which may be separate ambient lightsensors. When the ambient light levels drop below a threshold level, thecolor mode of the imaging sensor may be turned off, such that theimaging sensor operates in a monochromatic or black and white mode insuch low light conditions, thereby providing an enhanced image to thedisplay for viewing by the driver of the vehicle. Also, the illuminationsources (which are preferably infrared or near infrared illuminationsources or LEDs) may be activated when the ambient light levels are low,so as to provide additional, substantially non-visible light to theexterior scene. Optionally, the illumination sources may be activated toilluminate the targeted area to increase the contrast ratio in thedisplayed images to a desired amount in response to the contrast ratiofalling below a minimum acceptable viewing contrast ratio. Because theimaging sensors may then be operating in a black and white mode, theinfrared illumination emitted by the illumination sources will notresult in washed out or saturated or distorted color images. Also,because the imaging sensor may have a peak sensitivity in the infraredor near infrared range, and because the illumination sources may beinfrared emitting sources, the imaging sensor may be capable ofcapturing images in very low lighting conditions, whereby theillumination for the imaging sensor is provided by the infraredillumination sources.

Optionally, when the imaging sensor is operating in the color mode, themicrocontroller may adjust or correct the color balance via anadjustment of the pixel output for each of the color sensing pixels ofthe pixelated imaging array sensor. The present invention thus mayprovide a dynamic color balance adjustment function for a vehicularcolor exterior-viewing camera, such as one viewing rearward of thevehicle or forward of the vehicle or sideways of the vehicle, such asmay be achieved by placing the camera module with integrated auxiliaryillumination into an exterior rearview mirror assembly with its field ofview directed toward and onto a ground surface adjacent the side body ofthe vehicle (in this regard, and when auxiliary illumination isrequired, and when the camera-equipped exterior mirror assembly includesa visible light emitting ground illumination/security light, such as aredisclosed in U.S. Pat. Nos. 6,276,821; 6,176,602; 5,823,654; 5,669,699;5,497,306; and 5,371,659, which are hereby incorporated herein byreference, the ground illumination/security light may optionally beselectively actuated to add additional auxiliary illumination in certaincircumstances, such as when about to or first starting to drive thevehicle from a parked position). Preferably, such dynamic adjustment ofcolor balance is achieved by determination of the level of near-infraredradiation incident the camera module and by using this determined level(via a closed-loop or an open-loop control algorithm) to adjust thecolor balance and/or other characteristics (such as selection of themonochrome or black and white mode) of the video camera system employed.Other camera functions, such as iris function or exposure function, mayoptionally be similarly dynamically adjusted commensurate with adetected ambient near-infrared or other light level at the cameramodule. The present invention also finds applicability to interior cabinmonitoring systems.

Changes and modifications to the specifically described embodiments maybe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of appendedclaims, as interpreted according to the principles of patent law.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A camera module for avision system of a vehicle, said camera module comprising: a housingcomprising a base portion and a lens portion, wherein said lens portionof said housing and said base portion of said housing comprise plasticmaterial, and wherein said base portion is formed as a first injectionmolded part and said lens portion is formed as a second injection moldedpart separate from said base portion; wherein said base portion of saidhousing comprises a first mating portion and wherein said lens portionof said housing comprises a second mating portion; a circuit elementincluding an imaging sensor and associated circuitry, wherein saidimaging sensor comprises a CMOS imaging sensor having a dynamic range ofgreater than approximately 100 dB and less than approximately 120 dB,and wherein said dynamic range of said imaging sensor follows, at leastin part, a non-linear response curve; a lens; wherein said first matingportion of said base portion and said second mating portion of said lensportion are welded together to substantially limit water intrusion intosaid camera module and wherein said camera module comprises shielding tolimit or reduce electronic noise; and wherein said camera module isconfigured for mounting at a rear portion of a vehicle equipped withsaid camera module, and wherein, when said camera module is mounted atthe rear portion of the equipped vehicle, said imaging sensor has arearward field of view, and wherein said camera module, when mounted atthe rear portion of the equipped vehicle, is associated with a backupassist system of the equipped vehicle.
 2. The camera module of claim 1,further comprising a transparent cover at an end of said lens portionopposite said second mating portion, and wherein said field of view ofsaid imaging sensor is through said transparent cover, and wherein saidtransparent cover is welded at said end of said lens portion tosubstantially seal said transparent cover at said lens portion.
 3. Thecamera module of claim 1, wherein said dynamic range of said imagingsensor follows, at least in part, a linear response curve up toapproximately 62 dB.
 4. The camera module of claim 3, wherein saiddynamic range of said imaging sensor follows, at least in part, saidnon-linear response curve above approximately 62 dB.
 5. The cameramodule of claim 1, wherein said backup assist system is operable todetect an object in the rearward field of view of said imaging sensor.6. A camera module for a vision system of a vehicle, said camera modulecomprising: a housing comprising a base portion and a lens portion,wherein said lens portion of said housing and said base portion of saidhousing comprise plastic material, and wherein said base portion isformed as a first injection molded part and said lens portion is formedas a second injection molded part separate from said base portion;wherein said base portion of said housing comprises a first matingportion and wherein said lens portion of said housing comprises a secondmating portion; wherein said first mating portion of said base portionand said second mating portion of said lens portion are welded togetherto substantially limit water intrusion into said camera module; acircuit element including an imaging sensor and associated circuitry,wherein said imaging sensor comprises a CMOS imaging sensor having adynamic range of greater than approximately 100 dB; wherein said lensportion includes a lens providing an optical path to said imaging sensorat said circuit element; and wherein said camera module is configuredfor mounting at a rear portion of a vehicle equipped with said cameramodule, and wherein, when said camera module is mounted at the rearportion of the equipped vehicle, said imaging sensor has a rearwardfield of view, and wherein said camera module, when mounted at the rearportion of the equipped vehicle, is associated with a backup assistsystem of the equipped vehicle, and wherein said backup assist system isoperable to detect an object in the rearward field of view of saidimaging sensor.
 7. The camera module of claim 6, wherein said cameramodule comprises shielding to limit or reduce electronic noise.
 8. Thecamera module of claim 6, wherein, responsive to processing image datacaptured by said camera module, said backup assist system is operable todetermine a distance to an object detected in the rearward field of viewof said imaging sensor.
 9. The camera module of claim 6, wherein saiddynamic range of said imaging sensor follows, at least in part, anon-linear response curve.
 10. The camera module of claim 9, whereinsaid dynamic range of said imaging sensor follows, at least in part, alinear response curve up to approximately 62 dB and wherein said dynamicrange of said imaging sensor follows, at least in part, said non-linearresponse curve above approximately 62 dB.
 11. The camera module of claim6, further comprising a transparent cover at an end of said lensportion, and wherein said field of view of said imaging sensor isthrough said transparent cover.
 12. The camera module of claim 11,wherein said transparent cover is welded at said end of said lensportion of said housing to substantially at least one of seal and securesaid transparent cover at said lens portion of said housing.
 13. Thecamera module of claim 11, further comprising a heating element operableto heat said transparent cover to defrost or defog said transparentcover.
 14. A camera module for a vision system of a vehicle, said cameramodule comprising: a housing comprising a base portion and a lensportion, wherein said lens portion of said housing and said base portionof said housing comprise plastic material, and wherein said base portionis formed as a first injection molded part and said lens portion isformed as a second injection molded part separate from said baseportion; wherein said base portion of said housing comprises a firstmating portion and wherein said lens portion of said housing comprises asecond mating portion; a circuit element including an imaging sensor andassociated circuitry, wherein said imaging sensor comprises a CMOSimaging sensor having a dynamic range of greater than approximately 100dB, and wherein said dynamic range of said imaging sensor follows, atleast in part, a linear response curve up to approximately 62 dB andwherein said dynamic range of said imaging sensor follows, at least inpart, a non-linear response curve above approximately 62 dB; whereinsaid first mating portion of said base portion and said second matingportion of said lens portion are sealed together to substantially limitwater intrusion into said camera module; and wherein said camera moduleis configured for mounting at a rear portion of a vehicle equipped withsaid camera module, and wherein, when said camera module is mounted atthe rear portion of the equipped vehicle, said imaging sensor has arearward field of view, and wherein said camera module, when mounted atthe rear portion of the equipped vehicle, is associated with a backupassist system of the equipped vehicle.
 15. The camera module of claim14, wherein said CMOS imaging sensor has a dynamic range of less thanapproximately 120 dB.
 16. The camera module of claim 14, furthercomprising a transparent cover at an end of said lens portion oppositesaid second mating portion, and wherein said field of view of saidimaging sensor is through said transparent cover, and wherein saidtransparent cover is welded at said end of said lens portion tosubstantially seal said transparent cover at said lens portion.
 17. Thecamera module of claim 14, wherein a control associated with said backupassist system of the equipped vehicle is operable to process imagescaptured by said imaging sensor.
 18. The camera module of claim 17,wherein said backup assist system is operable to detect an object in therearward field of view of said imaging sensor.
 19. The camera module ofclaim 18, wherein, responsive to processing said captured images, saidcontrol is operable to determine a distance to an object detected in therearward field of view of said imaging sensor.
 20. The camera module ofclaim 14, further comprising a metallic shield, wherein said metallicshield is electrically grounded, and wherein said metallic shieldcomprises one of (a) a stamped metal shielding, (b) a stamped metalshielding formed by vacuum metalizing a shield layer of said plastichousing, and (c) a metallic foil.